HELICAL COIL · PDF fileHeatec helical coil heaters used in the Hot Mix Asphalt industry. ......

AN ASTEC COMPANYHEATEC

HELICAL COIL HEATERSHC AND HCS SERIES

• OPERATION• MAINTENANCE• TROUBLESHOOTING

Copyright 2002 Heatec, Inc.Heatec retains copyright on all text and graphic images in this manual. This manual is also available in electronic form as a PDF file from our website Heatec.com. You may download the file and make a single printed copy for personal use.

You may NOT print multiple copies of this manual or any portions thereof without the express written permission of Heatec. You may NOT distribute electronic copies of this manual. Moreover, you may NOT “mirror” or include any portion of this manual in other documents without our express permission.

Following the instructions in this manual will help you avoid serious injury or death. Read the manual in its entirety before performing any of the operations. Pay special attention to hazard warnings that appear in this manual and on our heaters. These warnings identify known hazards, their severity and how you can avoid them.

The warnings appear at appropriate places throughout this manual. They are repeated below to increase your awareness and as a

SAFETYpreview of those that follow. Be sure to read the instructions that accompany these notices where they appear.

Please be aware that safety is a part of all procedures and instruc-tions presented in this manual. Consequently, if you do not follow specific instructions given in the manual, you could create unfore-seen safety hazards.

This manual supersedes and replaces all previous manuals for Heatec helical coil heaters used in the Hot Mix Asphalt industry.

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Contents

INTRODUCTION .......................................................................................................................3Intended users ................................................................................................................................................................. 3Scope............................................................................................................................................................................... 3The difference between HC and HCS heaters ................................................................................................................... 3Drawings and photos are typical ...................................................................................................................................... 3OPERATION ............................................................................................................................3Thermal fluid—choosing the right product...................................................................................................................... 3Thermal fluid—how much do you need?......................................................................................................................... 3Thermal fluid—prolonging its life ................................................................................................................................... 3Getting ready for startup .................................................................................................................................................. 4Setting controllers............................................................................................................................................................ 4Filling system with thermal fluid ...................................................................................................................................... 4Purging the system.......................................................................................................................................................... 5Shutting down heater....................................................................................................................................................... 7Testing heater on natural gas........................................................................................................................................... 7Flame scanner precaution ................................................................................................................................................ 7Removing fuel pump coupling ......................................................................................................................................... 8Starting heater for routine operation................................................................................................................................ 8MAINTENANCE ........................................................................................................................9Importance....................................................................................................................................................................... 9How to recognize an out-of-tune-burner.......................................................................................................................... 9Cleaning strainer .............................................................................................................................................................. 9Thermal fluid—inspection and analysis ........................................................................................................................... 9Bleeding air from the circulating pump.......................................................................................................................... 10Readjusting low combustion air switch ......................................................................................................................... 10Cleaning the helical coil.................................................................................................................................................. 10Checking the low media level switch.............................................................................................................................. 10Cleaning sludge from expansion tank ............................................................................................................................ 10Checking the transformer in modulating actuator TZ4-1................................................................................................ 11Checking resistor board and motor in modulating actuator TZ4-1................................................................................. 11Checking the flame scanner ........................................................................................................................................... 11Adjusting pilot gas pressure regulator ........................................................................................................................... 11Re-tuning UDC 3300 Controller ..................................................................................................................................... 11Understanding tune functions of the UDC 3300 Controller ............................................................................................ 12

Understanding the proportional band (PROP BD)................................................................................................... 12Understanding RSET RPM...................................................................................................................................... 13Understanding RATE MIN....................................................................................................................................... 14

TROUBLESHOOTING................................................................................................................ 27General........................................................................................................................................................................... 27Make sure you know functions of control panel lights and switches ............................................................................. 27Don’t overlook the simple things ................................................................................................................................... 27Pay special attention to the limit circuit ......................................................................................................................... 27Understanding the wiring diagram................................................................................................................................. 27

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Understanding the control panel .................................................................................................................................... 28FIREYE FLAME MONITOR ................................................................................................................................................................................... 28

MANUAL RESET switch ....................................................................................................................................................................................... 28

MODULATING CONTROLLER .............................................................................................................................................................................. 28

HIGH MEDIA TEMP. CONTROLLER ..................................................................................................................................................................... 29

POWER ON indicator light.................................................................................................................................................................................... 29

HEAT DEMAND indicator light.............................................................................................................................................................................. 29

LOW MEDIA LEVEL indicator light ...................................................................................................................................................................... 29

HIGH FUEL GAS PRESS. indicator light ............................................................................................................................................................... 30

LOW FUEL GAS PRESS. indicator light................................................................................................................................................................ 30

HIGH MEDIA TEMP. indicator light ...................................................................................................................................................................... 30

HIGH STACK TEMP. indicator light ...................................................................................................................................................................... 30

CIRC. PUMP AUX. CONTACTS indicator light ...................................................................................................................................................... 30

LOW MEDIA PRESS. (OR FLOW) indicator light .................................................................................................................................................. 30

COMB. AIR AUX. CONTACTS indicator light ........................................................................................................................................................ 31

LIMITS MADE indicator light................................................................................................................................................................................ 31

IGNITION ON indicator light................................................................................................................................................................................. 31

GAS VALVE ON indicator light ............................................................................................................................................................................. 32

OIL VALVE ON indicator light............................................................................................................................................................................... 32

HEATER ALARM indicator light............................................................................................................................................................................ 32

BLOWER ON indicator light.................................................................................................................................................................................. 32

LOW FIRE HOLD-NORMAL switch....................................................................................................................................................................... 32

CIRC. PUMP OFF-ON switch ................................................................................................................................................................................ 32

HEATER CONTROL OFF-ON switch ...................................................................................................................................................................... 32

HEATER ALARM OFF-ON switch .......................................................................................................................................................................... 32

HEATER ALARM horn .......................................................................................................................................................................................... 32

GAS-OIL switch.................................................................................................................................................................................................... 32

AUX. PUMP OFF-ON switch ................................................................................................................................................................................. 32

Rotary door-mounted operating handle ............................................................................................................................................................... 32

List of FiguresFigure 1. HC heater with manifold, auxiliary (side)

pumps and combustion air preheaterFigure 2. HCS Single circuit heaterFigure 3. Stationary plant—Thermal fluid capacityFigure 4. Relocatable plant—Thermal fluid capacityFigure 5. Portable plant—Thermal fluid capacityFigure 6. Heater Thermal fluid capacityFigure 7. Gauge indications for heater normal operationFigure 8. Typical control panel for HC heaterFigure 9. Location of components on LH side of HCS heaterFigure 10. Location of components on RH side of HCS heaterFigure 11. Wiring diagramFigure 12 Fluid pressure gage installed in inlet pressure

gauge portFigure 13. Drain valve installed in strainer flangeFigure 14. Opening and closing valves

Figure 15. Removing fuel pump couplingFigure 16. Valve settings for operating modesFigure 17. Suggested set points for High Media

Temp. ControllerFigure 18. Close-up views for key components on

HC (manifold) heaterFigure 19. Understanding proportional control

(Optimum heater size)Figure 20 Understanding proportional control

(Oversized heater)Figure 21. Understanding proportional control

(Undersized heater)Figure 22. Proportional controlFigure 23. Proportional control with integral correctionFigure 24. Proportional control with integral and

derivative correctionFigure 25. Lubrication requirements

List of AppendicesAppendix A. Logic Flow Diagram Appendix B. Programming Honeywell UDC 3300 Appendix C. Programming Honeywell UDC 2300

Appendix D. Maintenance ScheduleAppendix E. Troubleshooting Table

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INTRODUCTIONIntended users This manual is intended for use by qualified asphalt plant operators and maintenance personnel. Qualified persons are those who understand electrical shock hazards and how to avoid them. Such persons are also familiar with the burn hazards of working with liquid asphalt and thermal fluids heated to temperatures in excess of 300 degrees F.

Some procedures require setting and testing parts inside the heater electrical control panel while it is open and electrical power is turned on. This should be done only by qualified persons using electrical testers to make sure wires and terminals they may touch are deenergized so that no electrical power is present.

ScopeThe manual covers standard HC and HCS heaters. New information that becomes available after this manual has been printed will be attached to the last page of this manual. Always check for new information before proceeding.

The difference between HC and HCS heatersThe HC series of heaters has a manifold that distributes thermal fluid to multiple thermal fluid circuits that are independently controlled. (See Fig. 1.) The HCS series does not have a manifold, but has a single thermal fluid circuit that circulates through the heater and through various tanks and equipment being heated. (See Fig. 2.) (Also see inside back cover.)

Both the HC and HCS series of heaters have an operator control panel that varies somewhat according to the number of thermal fluid circuits and options.

Drawings and photos are typicalPlease note that all drawings and photos in this manual are typical. Locations and appearances of components on your heater may differ somewhat from those shown. Because of differences in heaters, some instructions may not apply to your heater. So, just disregard instructions that don’t apply and use the ones that do apply.

OPERATIONThermal fluid—choosing the right productChoosing a suitable thermal fluid for your heating system is extremely important. Most of the major oil companies offer suitable products known as heat transfer oil. Always choose a heat transfer oil designed specifically for use in thermal fluid heating systems.

Do not use lubricating oils, turbine oils, diesel fuels and hydraulic fluids. They are not suitable for use in Heatec heaters! Moreover they should not be used in any thermal fluid heating system normally used at asphalt plants. Unsuitable fluids can lead to the following problems:

• Accumulation of sludge in the expansion tank • Carbon deposits in the heating coils • Failure of pumps • Clogging of jumpers in hot oil jackets of asphalt lines • Greatly increased risk of fire

Fluid products designed specifically for heat transfer have special properties. They include additives that help maximize heat transfer and minimize oxidation. Oxidation is a common problem with fluids heated over 300 degrees F unless they are designed for those temperatures. Oxidation significantly degrades the thermal fluid and contributes to the problems listed above.

Thermal fluid—how much do you need?Before initially filling your heating system with thermal fluid try to estimate how much to have on hand for startup. Thereafter, you should know exactly how much is required. Figures 3, 4, 5 and 6 can help you estimate the amount needed

for typical plants. If your plant components differ from the ones listed, add or subtract accordingly.

Thermal fluid—prolonging its lifeYou can prolong the life of the thermal fluid in your heating system by using nitrogen to minimize oxidation. Oxidation can cause rapid deterioration of fluid when heated to temperatures over 300 degrees F as required in heating asphalt. Oxidation also produces sludge, which can build up in oil lines, jumpers, heating coils, and in the expansion tank of the heater. Needless to say, sludge can significantly reduce the performance of your heating system and lead to costly cleanouts.

When the expansion tank is vented, it lets in air from the surrounding atmosphere. The air contains oxygen, which causes oxidation when it contacts the hot oil in the expansion tank. Replacing air with nitrogen greatly minimizes oxidation.

We offer a preassembled, pre-tested nitrogen system that has proven very effective. It is an option on new heaters and can be retrofitted to existing heaters. The new system includes a nitrogen shutoff valve, a secondary nitrogen pressure regulator, a check valve, a pressure gauge, a back-pressure regulator, and a vent valve. You will need to provide your own nitrogen bottle and regulator for use with our new system.

Older heaters had a pressure relief valve at the end of the expansion tank overflow pipe. The valve provided relief of back pressure when a nitrogen bottle was connected to the end of the overflow pipe. However, this valve was prone to sticking open causing loss of nitrogen.

The nitrogen system should not be connected to the tank until after the heater has been purged free of air and water.

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Getting ready for startup The procedure assumes the following conditions:

• The heater has a combination gas-oil burner.• The incoming gas supply line pressure is 1 psig max.• You will use a propane bottle for the gas pilot on

combination gas-oil burners if gas is shut off. Gas pressure of the bottle should not exceed 10 psi.

• The heater is properly installed, piped, and wired.• The thermal fluid system to be heated is fully piped and

leak-tested.• There is no thermal fluid in the heater or in its piping

circuits.

Procedure:

1. Make sure the power disconnect switch (the handle) on the control panel (Fig. 8) is set to OFF.

2. Make sure the switches marked HEATER CONTROL and CIRC. PUMP are set to OFF.

3. For HC heaters, make sure all switches marked AUX. PUMP are set to OFF.

4. Open the control panel and turn on all breakers. There are four toggle breakers and two rotary breakers. HC heaters have an additional rotary breaker for each auxiliary pump.

5. Install a fluid pressure gauge (Fig. 12) (not supplied) in the inlet pressure gauge port (W, Fig. 10.) Gauge should have a range of 0 to 100 psi. Coat threads with high temperature pipe thread sealant such as Rectorseal No. 5. Improperly sealed threads will result in leakage of thermal fluid.

6. Make sure the shutoff valve (Y, Fig. 10) for low media pressure switch is open.

7. Make sure the two shutoff valves on the sight gauge (D, Fig. 10) are open.

8. Install drain valve (Fig. 13) (not supplied) in the plug port of the strainer (Q, Fig. 10). Be sure to coat threads with a high temperature pipe thread sealant such as Rectorseal No. 5. Improperly sealed threads will result in leakage of thermal fluid.

9. Set the switch labeled HEATER ALARM to OFF while you are working near the heater. This setting turns off the alarm horn (which is extremely loud), but does not turn off the light labeled HEATER ALARM.

10. Set the controllers. (Refer to instructions on setting controllers.)

Setting controllers1. Set the power disconnect switch (the handle) on the

control panel (Fig. 8) to ON.

The light labeled POWER ON should come on.

2. Make sure the MODULATING CONTROLER and HIGH MEDIA TEMP. CONTROLLER (Fig. 8) are programmed according to the supplementary information provided by Heatec for Honeywell UDC 3300 and UDC 2300

controllers. (This information is on sheets laminated in plastic and stored inside the control panel. If you do not have the sheets, consult Appendix B and C in this manual).

The Honeywell UDC 3300 is the MODULATING CONTROLER. The Honeywell UDC 2300 is the HIGH MEDIA TEMP. CONTROLLER.

Pay particular attention to A2S1 VAL (Alarm 2 Setpoint 1 Value) on the MODULATING CONTROLER. It should be set at 200 degrees F. This setting controls the modulating burner’s low fire range. With this setting, the burner will remain in low fire until thermal fluid temperature reaches 200 degrees F. Then the burner will switch to high fire before modulating. This is a safeguard to prevent degradation and spillover of thermal fluid during startups.

3 Adjust the set point on the MODULATING CONTROLLER (Fig. 8) to 200 degrees F. To adjust set point, use the up / down arrows on the controller. Do not adjust the set point above 200 degrees F at this time.

4. Adjust the set point on the HIGH MEDIA TEMP. CONTROLLER (Fig. 8) to 250 degrees F.

. The HIGH MEDIA TEMP. CONTROLLER shuts down the heater if the temperature of the thermal fluid reaches this set point.

5. Set the power disconnect switch (the handle) on the control panel (Fig. 8) to OFF.

Filling system with thermal fluidThis procedure can take 2 hours or longer, depending on the size of the system.

1. Set the power disconnect switch (the handle) on the control panel (Fig. 8) to ON.

2. Set valves as indicated in Fig. 16 for purge. (See also Fig. 14)

3. For HC heaters, open all auxiliary valves on the manifold. If any port on the manifold is not in use, make certain it is fitted with a blind flange. An unsealed port will result in spillage of thermal fluid.

4. Make sure all valves in thermal fluid circuits connected to the heater are open.

5. Make sure drain valve (Fig. 13) is closed.

6. Remove the cap from the expansion tank filler (B, Fig. 10). Add thermal fluid to the expansion tank until fluid level reaches 12 inches in sight gauge.

Leave the cap off of the expansion tank filler. Excess air will exit through this opening as you circulate fluid.

7. Set the switch labeled CIRC. PUMP to ON (Fig. 8). The circulating pump (V, Fig. 10) should begin to operate.

The pump may cavitate intermittently during the fill and purge cycles as trapped air escapes from the system. Cavitation can be recognized by a rattling sound. Observe the inlet pressure gauge (Fig. 12). If the gauge oscillates it

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is an indication that trapped air is escaping the system.

Note: If the circulation pump cavitates and does not stop, check the inlet pressure gauge. If the gauge indicates a continuing drop in pressure, the strainer may be clogged. See section titled Cleaning strainer. You may have to clean the strainer several times during start-up of heater.

Observe fluid level in the sight gauge. When level drops to about 3 inches, set the switch labeled CIRC. PUMP to OFF (Fig. 8). This is a precaution to avoid drawing air into the system.

8. Add thermal fluid until level reaches 12 inches in the sight gauge.

9. Set the switch labeled CIRC. PUMP to ON (Fig. 8). The circulating pump (V, Fig. 10) should begin to operate.

10. Observe fluid level in the sight gauge. When level drops to about 3 inches, set the switch labeled CIRC. PUMP to OFF (Fig. 8).

For HCS heaters, continue this fill and circulate cycle. Gradually add less fluid until level stabilizes at 3 inches in the sight gauge. This is the normal “cold” fluid level. Proceed to step 17.

For HC heaters, continue this fill and circulate cycle until level stabilizes at 12 inches.

11. While the circulation pump is operating, set the switch labeled AUX. PUMP #1 to ON (Fig. 8). Auxiliary pump #1 at the manifold should begin to operate.

The auxiliary pump may cavitate, producing the same rattling sound mentioned earlier. This may continue intermittently throughout the fill and purge phases.

12. Observe fluid level in the sight gauge. If fluid level drops to about 3 inches, set the switches labeled CIRC. PUMP and AUX. PUMP #1 to OFF (Fig. 8).

13. Add thermal fluid until level reaches 12 inches in the sight gauge.

14. Set the switches labeled CIRC. PUMP and AUX. PUMP #1 to ON (Fig. 8). The circulating pump (V, Fig. 10) should begin to operate. Auxiliary pump #1 at the manifold should begin to operate.

Observe fluid level in the sight gauge. If fluid level drops to about 3 inches, set the switches labeled CIRC. PUMP and AUX. PUMP #1 to OFF (Fig. 8).

Continue this fill and circulate cycle until level stabilizes at 12 inches.

15. While the circulating pump and auxiliary pump #1 are operating, set the switch labeled AUX. PUMP #2 to ON (Fig. 8). Auxiliary pump #2 at the manifold should begin to operate.

Observe fluid level in the sight gauge. If fluid level drops to about 3 inches, set the switches labeled CIRC. PUMP, AUX. PUMP #1 and AUX. PUMP #2 to OFF (Fig. 8).

Add thermal fluid until level reaches 12 inches in the sight gauge.

Set the switches labeled CIRC. PUMP, AUX. PUMP #1 and AUX. PUMP #2 to ON (Fig. 8).

16. Continue the fill and circulate cycles as outlined above. Add one auxiliary circuit at a time until the circulating pump and all auxiliary pumps on the manifold are operating. Gradually add less fluid until level stabilizes at 3 inches. This is the normal “cold” fluid level.

17. Replace cap on the expansion tank filler.

Note: At this point, all air should be out of the system. However, the system must be purged while the burner is operating to remove all water and steam.

18. Set all switches labeled AUX. PUMP to OFF (Fig. 8).

19. Set switch labeled CIRC. PUMP to OFF (Fig. 8).


Purging the systemThis procedure requires firing the burner and heating the thermal fluid. The burner has been factory tested. Factory settings should be adequate for all operations covered in this procedure. However, burner tuning can be affected by local altitude or other atmospheric conditions and should be re-tuned after initial operation. See the section titled “How to recognize an out-of-tune burner” later in this manual. Only a thoroughly qualified burner technician should re-tune the burner.

Note: Purging the system can take from two hours to two days or longer, depending on the amount of moisture in the system.

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2. Make sure the MODULATING CONTROLLER and the HIGH MEDIA TEMP. CONTROLLER are set per previous instructions.

3. Make sure thermal fluid system is filled per previous instructions. Thermal fluid level should be 3 inches in the sight gauge (D, Fig. 10.)

4. Make sure drain valve (Fig. 13) is closed.

5. Make sure valves are set as indicated in Fig. 16 for purge. (See also Fig. 14.)

6. For HC heater, make sure the auxiliary valves on the manifold are open.

7. Set the switch labeled FUEL SELECTOR (Fig. 8), to OIL.

Note: On heaters with natural gas-oil combination burners, we recommend purging while operating on oil. However, the heater must also be tested while operating the burner on natural gas as indicated in later parts of these instructions.

8. Open valve in fuel oil supply line to heater.

9. Make sure the Pilot gas manual shutoff valve (H, Fig. 9) is open.

10. Make sure these valves are closed:

• Main gas manual shutoff valve (I, Fig. 9)• Secondary manual gas shutoff valve (R, Fig. 9)

11. Set the switch labeled CIRC. PUMP to ON (Fig. 8).

12. For HC heaters, set all switches labeled AUX. PUMP to ON.

13. Set the MODULATING CONTROLLER (Fig. 8) to manual. The message MAN should appear in the upper portion of the display.

The message OUT (burner output) should appear in the lower portion of the display. Adjust the burner output to 0.0%.

Note: The output’s lowest setting is –5.0%, not 0.0%. Make sure you set it at 0.0%.

14. Set the switch labeled LOW FIRE HOLD to NORMAL (Fig. 8.)

15. Set the switch labeled HEATER CONTROL to ON (Fig. 8.)

• The combustion air blower should come on.

• All lights on the two left columns of the panel should come on except HIGH FUEL GAS PRESS. and LOW FUEL GAS PRESS.

• The Fireye flame monitor (Fig. 8.) should operate the modulating actuator through high fire purge and low fire purge. The messages HIGH FIRE PURGE and LOW FIRE PURGE should show in the display. This will take approximately 1-1/2 minutes.

• The amber light labeled IGNITION ON will come on for approximately 10 seconds. The Fireye flame monitor (Fig. 8.) should display the message PTFI FLAME SIGNAL (Pilot flame Trial For Ignition). The amber light labeled OIL VALVE ON should come on.

• After 10 seconds, the burner should ignite the main flame. The Fireye flame monitor should display the message MTFI FLAME SIGNAL (Main flame Trial For Ignition) for approximately 10 seconds.

• The Fireye flame monitor should display the message AUTO FLAME SIGNAL. This indicates that the burner has ignited properly.

16. Observe the MODULATING CONTROLLER (Fig. 8.) The temperature of the thermal fluid should rise to the set point of 200 degrees F. Water and steam will exit the overflow pipe (W, Fig. 9.) Operate the heater at this temperature until no water or steam exits the overflow pipe.

Note: This can take from 45 minutes to several hours, depending on the amount of moisture in the system.

17. On the HIGH MEDIA TEMP. CONTROLLER, reset the set point to 260 degrees F.

18. On the MODULATING CONTROLLER, reset the set point to 210 degrees F.

Observe the MODULATING CONTROLLER. The temperature of the thermal fluid should rise to its new set point of 210 degrees F. Operate the heater at this temperature until no water or steam exits the overflow pipe. This can take from 45 minutes to several hours.

19. On the HIGH MEDIA TEMP. CONTROLLER, reset the set point to 270 degrees F.

20. Reset the MODULATING CONTROLLER to 220 degrees F. Operate the heater until no steam or water exits the overflow pipe.

21. Continue this cycle of raising the set point on the HIGH MEDIA TEMP. CONTROLLER and the MODULATING CONTROLLER in increments of 10 degrees. Each time you raise the set point, operate the heater until no steam or water exits the overflow pipe. Continue this cycle until you reach the set point of 320 degrees F on the MODULATING CONTROLLER.

Note: 320 degrees F is a typical set point for heater operation at an asphalt plant. The desired set point at your facility may be higher.

Note: If fluid temperature does not reach any of these set points:

• Press the LOWER DISPLAY button on the MODULATING CONTROLLER until the message OUT appears in the lower portion of the display.

• Use the up arrow to set the output at 10.0 %.

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• The thermal fluid temperature should begin to rise toward the set point. If fluid temperature still does not rise to set point, increase output in increments of 10% as necessary. Use caution to avoid overheating thermal fluid and causing a spillover.

22. Adjust the set point on the HIGH MEDIA TEMP. CONTROLLER (Fig. 8.) See Fig. 17 for suggested settings. Note that the desired settings at your facility may differ from those shown.

23. Set the MODULATING CONTROLLER (Fig. 8) to auto. The letter A should appear in the upper portion of the display.

24. Set valves as indicated in Fig. 16 for Run. (See also Fig. 14.)

25. Check the inlet pressure gauge (Fig. 12). For correct pressures refer to Fig. 7.

Shutting down heater1. Set the switch marked HEATER CONTROL to OFF (Fig. 8).

2. Allow the circulation pump and the auxiliary pumps (HC heater only) to continue operating for approximately 10 minutes.

3. Set the switch marked CIRC. PUMP to OFF (Fig. 8.)

4. For HC heaters, set all switches marked AUX. PUMP to OFF.

5. Close the pilot gas manual shutoff valve (H, Fig. 9 .)

6. Close valve in the fuel oil supply line to heater.


8. Make sure these valves are closed:

• Main gas manual shutoff valve (I, Fig. 9).• Secondary gas manual shutoff valve (R, Fig. 9).• Pilot gas manual shutoff valve (H, Fig. 9.)

Testing heater on natural gas1. Make sure the power disconnect switch (the handle) on the

control panel (Fig. 8) is set to OFF.

2. Set the switch marked FUEL SELECTOR to GAS.

3. Open these valves:

• Main gas manual shutoff valve (I, Fig. 9).• Secondary gas manual shutoff valve (R, Fig. 9).• Pilot gas manual shutoff valve (H, Fig. 9.)

4. Make sure valve in fuel oil supply line is closed.

5. Make sure valves are set as indicated in Fig. 16 for Run. (See also Fig. 14.)


6. Set switch marked CIRC. PUMP to ON.

7. For HC heaters, set all switches marked AUX. PUMP to ON.

8. Set switch marked HEATER CONTROL to ON.


• All clear lights plus the LIMITS MADE light shown in Fig. 8 should come on.

• The Fireye flame monitor (Fig. 8.) should operate the modulating actuator through high fire purge and low fire purge. The messages HIGH FIRE PURGE and LOW FIRE PURGE should show in the display. This will take approximately 2 minutes.

• The amber light labeled IGNITION ON will come on for approximately 10 seconds. The Fireye flame monitor (Fig. 8.) should display the message PTFI FLAME SIGNAL (Pilot flame Trial For Ignition). The amber light labeled GAS VALVE ON should come on.



9. If you plan to operate the heater on gas for an extended time, remove the fuel pump coupling from the blower motor to avoid damaging the fuel pump. See section titled: Removing fuel pump coupling.

Flame scanner precaution The flame scanner and amplifier used on HC and HCS heaters are the non-self checking types . However, the flame monitor checks the flame scanner each time the heater is started. Consequently, it is extremely important that the heater cycles off and on a minimum of once every 12 hours.

If the heating system is highly stable (as it should be), the heater may not automatically cycle off and on that often. Therefore, to ensure that the flame scanner is okay, you should manually switch the heater off for a second or two and then back on. Do this once each morning and once again late in the day.

In the event that the flame scanner fails while the heater is operating, it may not shut the heater down. Thus, the scanner could allow the fuel valves to remain open, even if there is an inadvertent loss of flame. This would allow the heater and surrounding area to become saturated with unlit fuel, creating an extremely unsafe condition.

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If you try to restart a heater that has a defective flame scanner, the heater will not restart. Instead, the flame monitor will show the message FALSE FLAME. This indicates that the flame scanner or amplifier is bad and should be replaced. Never disconnect and reconnect the flame scanner or take any other action to circumvent the scanner in order to restart the heater. Instead, replace the defective scanner and amplifier. Otherwise, you could create an unsafe condition as described above.

Removing fuel pump coupling1. Shut down heater per previous instructions.

2. Turn off main circuit breaker (Q Fig. 18) and lock it off.

3. Remove the nuts from around the burner fan motor (T, Fig. 10).

4. Pull the burner fan motor out of the burner housing.

5. The fuel pump coupling will either come out with the burner motor or remain on the fuel pump. Pull off the coupling. (See Fig. 15.)

6. Re-install burner fan motor.

7. Unlock main circuit breaker (Q Fig. 18) and turn it on.

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��Starting heater for routine operation1. Set the power disconnect switch (the handle) on the

control panel (Fig. 8) to ON.

2. Set the switch labeled FUEL SELECTOR (Fig. 8.) to the fuel you wish to use (GAS or OIL).

3. Set valves as indicated in Fig. 16 for Run. (See also Fig. 14.)

4. For GAS:

Open the main gas manual shutoff valve (I, Fig. 9.)Open the secondary gas manual shutoff valve (R, Fig. 9.)Open the pilot gas manual shutoff valve (H, Fig. 9.)Make sure fuel oil supply to heater is shut off.

For OIL:

Open fuel oil supply to heater.Open the pilot gas manual shutoff valve (H, Fig. 9.)Make sure the main gas manual shutoff valve (I, Fig. 9.) is closed.Make sure the secondary gas manual shutoff valve (R, Fig. 9.) is closed.

5. Set the switch marked CIRC. PUMP to ON (Fig. 8.)

6. For HC heaters, set switches marked AUX. PUMP to ON for each of the auxiliary circuits you wish to heat.

7. Set the switch marked HEATER CONTROL to ON.


• All clear lights plus the LIMITS MADE light shown in Fig. 8 should come on.

• The Fireye flame monitor (Fig. 8.) should operate the modulating actuator through high fire purge and low fire purge. The messages HIGH FIRE PURGE and LOW FIRE PURGE should show in the display. This will take approximately 2 minutes.

• The amber light labeled IGNITION ON will come on for approximately 10 seconds. The Fireye flame monitor (Fig. 8.) should display the message PTFI FLAME SIGNAL (Pilot flame Trial For Ignition). The amber light labeled either GAS VALVE ON or OIL VALVE ON should come on, depending on which fuel you are using.



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MAINTENANCE

ImportanceHeatec HC and HCS heaters should be checked periodically according to the requirements set forth in Appendix D. Failure to properly maintain your heater could result in a fire or explosion.

How to recognize an out-of-tune burnerUnder normal operating conditions with a properly tuned burner, the heater should not smoke. The flame pattern, when viewed through the sight glass on the heater end plate should have a counter-clockwise swirl. The flame should be no longer than 1/3 the length of the coil. Flame diameter should be approximately 2/3 the diameter of the coil. Flame color on natural gas fuel should be bright blue. When fired from fuel oil, flame color should be bright yellow. The flame should be centered in the coil.

Only a thoroughly qualified burner technician should tune the burner. See the burner manual supplied with your heater for additional information. Look for the following conditions to see if the burner requires tuning:

Smoke. If smoke comes from the exhaust stack, it is a strong indication that the fuel-to-air ratio is out of adjustment. Black smoke indicates too much fuel in the mixture. White smoke indicates too much air.

Flame color. If the flame color becomes very light, there could be too much air in the mixture. If the flame color becomes dark and dull, there could be too much fuel. If the natural gas flame has noticeable yellow tips, there could be too much fuel.

Flame impingement. If the flame impinges on the coil, the diffuser could be bent or the nozzle could be clogged. Too much fuel in the fuel-to-air ratio can also cause impingement on the coil. Impingement reduces the life of the coil.

Unstable flame. If the flame pulsates or extends to lengths longer than 1/3 the length of the coil, the diffuser could be out of adjustment or the nozzle could be clogged.

If the flame has “tracers” or long extensions of flame that extend beyond 1/3 the length of the coil, the diffuser could be out of adjustment or the nozzle could be clogged.

Cleaning strainer1. Set the switch marked HEATER CONTROL to OFF (Fig. 8).

Allow the circulation pump and the auxiliary pumps (HC heater only) to continue operating for approximately 10 minutes.

2. Set the switch labeled CIRC. PUMP to OFF.

3. For HC heaters, set all switches labeled AUX. PUMP to OFF.

4. Set valves as indicated in Fig. 16 for Clean Strainer. (See also Fig. 14.)

5. Place a bucket or other container under the drain valve (Fig. 13). Container should be at least 5-gallon capacity.

NOTE: Wear chemical and heat resistant gloves as shown in Fig. 13.

6. Open drain valve to drain thermal fluid from the strainer. Do not re-use this fluid. Dispose of it properly.

7. Unbolt the square flange from the bottom of the strainer. Remove the flange, and the strainer basket will slide out.

8. Clean the strainer basket with fuel oil, then dry completely with compressed air.

9. Re-install the strainer basket and flange.

10. Close drain valve.

11. Install a cap on the drain valve (Fig. 13) to protect against accidental release of thermal fluid.

Thermal fluid—inspection and analysisThe thermal fluid should be analyzed at the end of the paving season, before the heating system is shut down for the winter. The analysis should be done by a specialist experienced and properly equipped to analyze chemical properties of the fluid. Fluid suppliers may do a free analysis for you. Or you may need to have an independent laboratory do the analysis. The sample should be taken while the heat is shut off and the fluid has cooled down somewhat, but while the system is circulating the fluid.

Although you cannot reliably tell if the fluid is okay by visually inspecting it, you may be able to detect problems. So, every time you inspect the strainer on the heater, be sure to watch for signs of problems with the thermal fluid. (After initial startup of the heater you should inspect the strainer once a month and clean it if it is dirty.) If appearance of the fluid shows sign of a problem, you should have the fluid analyzed. Watch for the following signs:

• Flakes of carbon

• Foam or milky appearance

• Presence of asphalt that may have leaked into the fluid

• Unusual thickening of the fluid

Remember, these may be early signs of a problem that could become more serious if allowed to continue. It is almost always better to correct problems at their early stages.

Page 11

Bleeding air from the circulating pump (V, Fig. 10)1. Make sure that the HEATER CONTROL switch (Fig. 8) is set

to OFF.

2. Close the valve number 4 (R, Fig.10) in the thermal fluid line at the helical coil inlet.

3. Observe pressure gauge (Fig. 12) between circulation pump and helical coil inlet valve. When gauge indicates normal operating pressure, open valve fully at inlet of helical coil. Normal operating pressures are shown in Fig. 7.

4. Repeat as necessary until pressure indication is steady at its normal pressure.

Readjusting low combustion air switch (H, Fig. 18)Note: You will need a circuit tester or an ohmmeter for this procedure.

1. Make sure that the HEATER CONTROL switch (Fig. 8) is set to OFF.

2. Remove cover from low combustion air switch (H, Fig. 18).

3. Remove wires from terminals inside switch.

4. Turn adjusting screw clockwise until switch opens.

5. Set circuit tester to read ohms or continuity.

6. Attach tester leads to terminals marked COMMON and NORMALLY OPEN.

7. Turn screw counterclockwise until circuit tester indicates continuity, which indicates that the switch has closed.

8. Turn adjusting screw counterclockwise an additional 1/2 turn.

9. Reconnect wires and replace cover.

Cleaning the helical coil1. Make sure that the HEATER CONTROL switch (Fig. 8) is set

to OFF and the heater has cooled down.

2. Turn off main circuit breaker (Q Fig. 18) and lock it off.

3. Remove the heater end cover plate (F, Fig. 10) from the end of the heater opposite the burner.

4. Use compressed air to blow soot off all exposed surfaces of the coil, including surfaces next to the insulation on the walls of the heater shell. Be careful not to damage insulation inside the shell.

Note: To accomplish this you will need a long pipe connected to the end of your compressed air hose. The pipe should have a series of holes along its length. The end of the pipe must be plugged.

5. Vacuum out the soot from inside the helical coil.

6. Replace the end plate.

Checking the low media level switch (K, Fig. 18) for proper operationBefore checking the switch for proper operation, confirm that the expansion tank (A, Fig. 10) has an adequate level of thermal fluid. Do this using a measuring stick through the filler opening (B, Fig. 10. If the tank has adequate fluid proceed with checking the switch as follows:

Open the control panel and turn on power to the panel while it is open.

Check for 120 Vac between terminal 50 and neutral (Fig. 11). If the voltage is present, the switch is closed and is okay.

If no voltage is present, the switch circuit is open and there is a problem with the switch. You can remove the screw-on cover plate from the back of the switch and see if there is a loose wire or an obvious problem with the micro-switch or the linkage that activates the switch. Otherwise, replace the entire switch, including the float portion.

Note: The switch has two parts: a switch housing and a float housing. The float housing protrudes inside the tank and seals the opening so that thermal fluid cannot escape. There is no opening between the float housing and the switch housing. (The float mechanism has a magnet that activates the switch inside the switch housing.) You can open or replace the switch housing without draining the expansion tank. However, you must drain the tank before removing the float housing.

Cleaning sludge from expansion tank (A, Fig. 10)Confirm that tank has sludge and needs cleaning. To do this, run a wooden stick through the filler all way to bottom of tank and try to move its tip back and forth in the fluid. If you detect resistance to its movement the tank has sludge. Withdraw stick and inspect its tip for further evidence of sludge. If sludge is present, clean the tank as follows:

1. Set switch HEATER CONTROL (Fig. 8) to OFF. Allow the circulation pump (and auxiliary pumps on HC heaters) to continue operating for approximately 10 minutes.

2. Set switch CIRC. PUMP to OFF. For HC heaters, set all switches labeled AUX. PUMP to OFF. Let the system cool.

3. Close Valves No. 1, 2 and 4 (M, L, and R, Fig. 10).

4. Place a container under the drain valve (Fig. 13). You will probably have to empty the container several times as you drain thermal fluid from the expansion tank.

NOTE: Wear chemical and heat resistant gloves as shown in Fig. 13.

5. Open drain valve to drain thermal fluid from expansion tank. Some sludge will drain out with the thermal fluid. Do not re-use this fluid. Dispose of it properly.

Page 11

6. Remove the drain valve, the square flange, and the strainer basket from the strainer (Q, Fig. 10).

NOTE: Sludge will exit the strainer. Make provisions to capture the sludge so you can dispose of it properly.

7. Insert a long spray nozzle from a pressure washer into the tank through the fill opening (B, Fig. 10). Wash until clean. Allow as much washing solution as possible to drain from the expansion tank.

8. Clean the strainer basket with fuel oil, then dry completely with compressed air.

9. Re-install strainer basket, square flange, and drain valve.

10. Refill tank with clean thermal fluid.

11. Purge system as instructed in OPERATION section.

12. After purge, set valves for RUN as indicated in Fig. 16.

Checking the transformer in modulating actuator TZ4-1 (C, Fig. 18)1. Make sure HEATER CONTROL switch (Fig. 8) is set to OFF.

2. Make sure there is 120 Vac on the primary winding of the transformer using an ac voltmeter.

3. Check for 24 Vac on its secondary winding. The transformer is defective if there is no voltage on its secondary winding.

Checking resistor board and motor in modulating actuator TZ4-1 (C, Fig. 18)1. Make sure HEATER CONTROL switch (Fig. 8) is set to OFF.

2. Make sure that the dip switch settings are correct as indicated on the wiring diagram. Use a ball-point pen to make sure that switches are fully depressed. (Partially depressed switches have been a problem in the past.)

3. Make sure its transformer is not defective. Refer to instructions above.

4. Disconnect wires from terminals R, W and B of the resistor board.

5. Temporarily connect a short jumper wire from terminals R to B. The motor of the actuator should go to high fire, which indicates that the motor is okay and its particular circuit on the resistor board is okay. Otherwise, either the motor or the resistor board is bad.

6. Temporarily connect a short jumper wire from terminals W to R. The motor of the actuator should go to low fire (if it is not already there), which indicates that the motor is okay and its particular circuit on the resistor board is okay. Otherwise, either the motor or the resistor board is defective and should be replaced.

7. Remove the resistor board.

8. Connect the two wires from the secondary side of the

transformer to terminals T1 and T2 of the circuit board where the resistor board was removed.

9. Using a short jumper wire, temporarily connect from terminal R to B on the circuit board. If the motor works, the resistor board is defective and should be replaced.

Checking the flame scanner (J, Fig. 18)1. Make sure that the HEATER CONTROL switch (Fig. 8) is set

to OFF.

2. Turn on power to the control panel while the front panel is open.

3 With no flame present, check for 560 Vac between terminals S1 and S2 using an ac voltmeter. (See Fig. 11.)

4. Remove the flame scanner.

5. Create a flame using a cigarette lighter, a torch or a match. Hold the flame in front of the scanner eye. The voltage should drop to about 340 Vac and the Fireye Flame monitor should show the message FALSE FLAME and should indicate a signal number. Otherwise, either the flame scanner or its amplifier is defective.

Adjusting pilot gas pressure regulator (U, Fig. 10)1. Connect a manometer to the tee of the pilot gas line where

it enters the burner.

2. Open the control panel and gain access to the flame monitor.

3. Turn on power to the control panel while the front panel is open.

4. Set HEATER CONTROL switch to ON and let the heater start through its purge cycle.

5. Without delay, remove red cover from Fireye flame monitor. Wait for the flame monitor to display the words IGNITION TIMING. Quickly place the switch on Flame monitor programmer marked CHECK/RUN to the position marked CHECK. This will hold the timing sequence while you adjust the regulator.

6. Adjust screw on regulator so that manometer indicates 3-inches W.C. or as specified for your burner in the burner manual.

7. Place flame monitor switch back to RUN. The timing sequence should continue and operation should be normal.

Re-tuning UDC 3300 ControllerOn many heaters the controller’s preset values provide satisfactory modulation control of the burner, so it is not necessary to re-tune it. However, it should be re-tuned if the temperature of the thermal fluid constantly overshoots its proportional band (PROP BD) causing the burner to frequently cycle on and off.

Page 13

Re-tuning should be done only after the heater and thermal fluid circuits have been filled with thermal fluid and purged free of air and water. There are two methods of re-tuning. One method is to use the Accutune function of the controller, which automatically tunes the controller. The other method is to manually reset three of the numerous functions that were preset according to instructions earlier in this guide. Again, do not re-tune the controller unless the heater shuts off and on frequently. Instructions for using both of these tuning methods follow.

Re-tuning UDC 3300 controller using “Accutune”Due to wide variations in heating systems and heater capacities, Accutune works fine on some heating systems, but not well on others. Accordingly, try Accutune before re-tuning the controller manually. If it does not work as well as expected, try re-tuning it manually. Follow these steps to use Accutune:

1. Press the SET UP button repeatedly until the lower dislay shows ACCUTUNE.

2. Press the FUNCTION button to show FUZZY in lower display. Make sure upper display shows DISABL.

3. Press FUNCTION button until ACCUTUNE shows in lower display. Use arrow key so that TUNE shows in upper display.

4. Press LOWER DISPLAY button to return to main display. Make sure the letter A (auto) shows in the display.

5. Press LOWER DISLAY button and up arrow button simultaneously. The letter T should appear in the upper display. This indicates that Accutune is underway. It could take from a few minutes to several hours. When it is complete the T will disappear and new values should appear for PROP BD, RATE MIN and RSET RPM. (You can abandon this tuning process by pressing the MANUAL/AUTO button.) If ACCUTUNE settings do not provide suitable operation, press the SET UP button until TUNING appears. Then proceed with manual re-tuning.

Re-tuning UDC 3300 contoller manuallyTo re-tune the controller manually, reset the values for the three tuning functions shown in the following table. This table presently shows their initial preset values. These values are the same as shown on the laminated sheets of supplementary information furnished with your heater and duplicated in Appendix B.) You will need to change these values.

Group Prompt

Function Prompt

Value or Selection

TUNING PROP BD 2.0

RATE MIN 0.08

RSET RPM 3.00

Resetting the values of the three functions is a matter of trial and error. It may be possible to improve control by increasing the values of all three. However, the value of only one function should be reset at a time.

Start by increasing PROP BD to 4.0. Operate the heater at its new setting to see its effect before making any other changes.

If you think further improvement is needed, reset RATE MIN to 1.00. Again, operate the heater at its new setting to see its effect before making any other changes.

If you think further improvement is needed, reset RSET RPM to 6.0. Again, operate the heater at its new setting to see its effect before making any other changes.

If you think further improvement is needed after resetting all three, repeat the sequence of changing the values of each function, one at a time. Here are some values to try:

• For PROP BD try values from 2.0 to 10.0.

• For RATE MIN try values from 0.08 to 5.00 (0.08 or less disables this function)

• For RSET RPM try values from 3.00 to 10.00 (Setting it to 1.00 is too low)

You don’t have to know what these functions do and how they work to achieve satisfactory operation. However, some understanding of them should prove helpful, so please read on for an explanation.

Understanding tune functions of the UDC 3300 ControllerUnderstanding the three tuning functions mentioned above is helpful when re-tuning the controller. These three functions are widely known as PID or Proportional-Integral-Derivative.

When combined, the proportional, integral, and derivative actions provide quick response to error, close adherence to set point, and control stability. A brief overview of these three functions is shown in the table that follows. A more detailed explanation is given after the table.

Page 13

PROMPT ON CONTROLLER MEANING

PROP BD A band of temperatures in which a change in the controller’s output is proportional to a change in temperature. The preset value for this band is a percentage of the process variable (PV) range. (PV range is the temperature range for the thermocouple used in the thermal fluid circuit.)

RATE MIN A correction to the controller’s proportional output based on the difference in thermal fluid temperature and its set point and the rate it is changing. This correction is obtained using a mathematical derivative and uses the preset value as a factor in the equation.

RSET RPM A correction to the controller’s output based on the difference in thermal fluid temperature and the set point and how long the difference has existed (integral time). The preset value for RSET RPM governs how many times or resets per minute the controller makes a correction.

Understanding the proportional band (PROP BD)The UDC 3300 controller has an output used to control heating of thermal fluid to maintain a temperature that the operator presets on the controller. This preset is known as set point or SP.

The controller senses thermal fluid temperature (known as process variable or PV) from a thermocouple. The controller processes the thermocouple signal and produces a control signal or output that it sends to Honeywell modulating actuator TZ4-1 (D, Fig. 9). The actuator responds by either increasing or decreasing the burner firing rate as required to maintain fluid temperature at the set point. Output of the controller is proportional when the thermal fluid temperatures are within a certain range known as the proportional band.

Please see Fig. 19 for a graph that depicts the characteristics of proportional control for a heater that is theoretically the optimum size. It helps in understanding the explanations given below.

In Fig. 19 the output of the controller that maintains the temperature of the thermal fluid at SP is labeled CONSTANT. This is the output of the controller when the error or deviation is zero while the heater is in a steady state. Theoretically, when the set point is the midpoint of the PV range, the constant will be 50 percent. However, the constant for our heaters is usually much less than 50 percent and in rare instances more than 50 percent. It varies because of numerous factors, such as the size of the heater, how well the piping is insulated, etc.

Fig. 20 shows the proportional control for a hypothetical heater that is oversized with an assumed constant of 25 percent. Fig. 21 shows the proportional control for a hypothetical heater that is undersized with an assumed constant of 75 percent.

In all cases, the proportional band is a percentage of the PV (process variable) range. The PV range is determined by what thermocouple is used to sense the temperature of the thermal fluid flowing out of the heater coil. The thermocouple most frequently used with Heatec heaters is a type J with a low range. It is known as “J-LOW” and appears on the controller as JTCL. Its low range can measure temperatures as low as 20 degrees F and as high as 770 degrees F. Accordingly, it has a range of 750 (770 minus 20) degrees and this becomes the PV (process variable) range. Thus, the value you set for the proportional band is a percentage of 750.

Setting the PROP BD to a value of 2 means 2 percent of 750 (or 15 degrees). Thus, a span of 15 degrees F is used as the proportional band. Accordingly, the output of the controller will be proportional over a span of 15 degrees, and this is the full modulating range or proportional band of the controller.

The SP (set point) is always somewhere within that proportional band, usually the center of the band. (The set point is the thermal fluid temperature you wish to maintain.) Heaters at most asphalt plants use a set point of 320 degrees F. So, we will use that as the set point in our explanations. Using 320 degrees F as the SP, the proportional band will range from 312.5 to 327.5 degrees F as shown in Fig. 19, 20 and 21. Controller outputs for temperatures between those two points are proportional.

However, the size or the heater in relation to the heat load affects the firing rate needed to maintain set point and other temperatures within the proportional band. Note the differences in firing rates for a heater of optimum size compared to heaters that are oversized and undersized as shown in Fig. 19, 20 and 21.

Fig. 19 shows the controller output for a heater of optimum size. Its output is at 100 percent when the temperature is at 312.5 degrees F. Its output is at 50 percent when the temperature is at the set point of 320 degrees F. Its output is at zero percent (or low fire) when the temperature is at 327.5 degrees F.

Fig. 20 shows the controller output for a heater that is oversized. Its output is at 50 percent when the temperature is at

Page 15

312.5 F. Output is at 25 percent when the temperature is at the set point of 320 degrees F. Its output is at zero percent (or low fire) when the temperature is at 327.5 F.

Fig. 21 shows the controller output for a heater that is undersized. Its output is at 100 percent when the temperature is at 312.5 F. Its output is at 75 percent when the temperature is at the set point of 320 degrees F. Its output is at 50 percent when the temperature reaches 327.5 F. Its output is at zero percent (or low fire) if the temperature exceeds 327.5 degrees F.

Understanding RSET RPM This setting of the controller results in a correction to the controller’s proportional output. The correction is based on both the size of the error (the difference between the SP and PV) and how long it lasts.

The term RSET RPM means reset in repeats per minute. The value you set as RSET RPM governs how frequently proportional action is repeated within each minute. Be careful not to confuse that term with RSET MIN, which means reset in minutes per repeat. The latter means there is one or more minutes between each repeat of proportional action. In either case, the reset is for integral time.

This correction is needed because of an inherent weakness of proportional control. Proportional control requires a significant error condition to create an output signal. Accordingly, proportional control alone can never actually achieve the desired condition. Some small amount of error, known as system offset will always be present. Fig. 22 shows the type of control response typical of proportional control alone. Note the offset from set point.

The integral action is designed to eliminate offset. Because the offset’s magnitude is relatively small, it cannot change the control signal significantly by itself. An integrating term is used to observe how long the error condition has existed, summing the error over time. The summation value becomes the basis for an additional control signal, which is added to the signal produced by the proportional term. The control loop then continues to produce a control action over time, allowing the elimination of offset.

Adding integral action to the controller output can:

• Respond to the presence of error in the control loop.

• Relate the magnitude of the control signal to that of the error.

• Respond to offset over time to achieve zero error—set point.

Fig. 23 shows the control response typically produced with proportional-integral control. The significant difference is the elimination of offset once the system has stabilized.

Understanding RATE MIN This setting of the controller results in a correction to the controller’s proportional output. The correction is based on both the size of the error (the difference between the SP and PV) and the rate it is changing.

The term RATE MIN refers to rate per minute, which can range from 0.00 to 10.00 (0.08 or less = OFF). The value you set as RATE MIN governs how much braking action is applied to the output of the controller as it corrects for error. This correction is applied only when the error is changing and increases when error changes faster.

This correction is needed because proportional control has a tendency to overshoot. Overshoot refers to a control loop’s tendency to overcompensate for an error condition, causing a new error in the opposite direction. Overshoot can cause unnecessary overheating.

Overshooting is corrected by a derivative action that provides an anticipatory function to exert a “braking” action on the control loop. The derivative term is based on the error’s rate of change. It observes how fast the PV approaches SP and produces a control action based on this rate of change. This additional action anticipates the convergence of PV and SP, in effect counteracting the control signal produced by the proportional and integral terms. The result is a significant reduction in overshoot.

Fig. 24 shows the effect of both integral and derivative actions to reduce overshoot and eliminate offset in proportional control.

Page 15

Figure 2. HCS Single circuit heater.

Figure 1. HC heater with manifold, auxiliary (side) pumps and combustion air preheater.

Page 17

Figure 3.

Figure 4.

Figure 6Figure 5.

Figure 7.

ModelFuel OilSupply

Pressure

Fuel OilReturn

Pressure

Coil InletPressure

Coil OutletPressure

Coil OutletThermometer**

ManifoldThermometer***

HCS-70 275-300 psi 70–180 psi 50–60 psi* 36–46 psi* 320°F —HCS-100 275-300 psi 70–180 psi 50–60 psi* 26–36 psi* 320°F —HCS-175 275-300 psi 70–180 psi 50–60 psi* 29–39 psi* 320°F —HCS-250 275-300 psi 70–180 psi 50–60 psi* 24–34 psi* 320°F —HC-120 275-300 psi 70–180 psi 25–30 psi 0–10 psi 320°F < 270°FHC-200 275-300 psi 70–180 psi 25–30 psi 0–10 psi 320°F < 270°FHC-300 275-300 psi 70–180 psi 25–30 psi 0–10 psi 320°F < 270°F

Gauge Indications For Heater Normal Operation

*These pressures may vary approximately 30 to 40 percent depending upon piping circuits.**Temperature at coil outlet should be same as set point. ***Temperature at manifold should be approximately 50 or more degrees less than set point.

Heatec HC-200 heater 159

Two 30,000 gallon horizontal coil tanks for virgin asphalt 462

One 25,000 gallon vertical asphalt tank for PMAC 45Heavy fuel preheater 30Double Barrel drum mixer 9 ft x 46 ft 10Drag conveyor, 42 inch x 100 ft 132Three 300-ton storage silos 210Traverse conveyor, 36 inch x 33 ft 44100 feet of asphalt piping, 4-inch dia 77230 feet of hot oil piping, 1-1/2 inch dia 24Plant Total 1193

Stationary Plant—Thermal Fluid Capacity (Gallons)

Model Coil Expansion Tank Total

HCS-70 35 25 60HCS-100 52 44 96HCS-175 89 70 159HCS-250 150 70 220HC-120 52 44 96HC-200 89 70 159HC-300 150 70 220

Amounts shown for expansion tanks are with tanks 1/4 full.

Heater Thermal Fluid Capacity (gallons)

Heatec HCS-100 heater 96

One 30,000 gallon Heli-tankfor asphalt 231Double Barrel drum mixer 7 ft x 35 ft 10

Drag conveyor on surge bin, 24 inch x 50 ft 6670 feet of asphalt piping, 4-inch dia 54150 feet of hot oil piping, 2-inch dia 26

Plant Total 483

Portable Plant—Thermal Fluid Capacity (Gallons)

Heatec HC-120 heater 96

Two 30,000 gallon horizontalcoil tanks for asphalt 462Double Barrel drum mixer 8ft x 39 ft 10Drag conveyor, 36 Inch x 95 ft 125Two 200-ton storage silos 44Traverse conveyor, 36 Inch x 14 ft 18100 feet of asphalt piping, 4-inch dia 77

230 feet of hot oil piping,1-1/2 inch dia 24

Plant Total 857

Relocatable Plant—Thermal Fluid Capacity (Gallons)

Page 17

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Figure 8. Typical control panel for HC heater.

Page 19Figure 9. Location of components on LH side of HCS heater.

A

C

D

E

F

G

HI

J

B

KLM

NO

RS

A. Low media level switchB. Exhaust stackC. High fl ue gas temperature switchD. Modulating actuatorE. BurnerF. Burner junction boxG. Main fuel oil valveH. Pilot gas manual shutoff valveI. Main gas manual shutoff valveJ. Auxiliary fuel oil valveK. Circulating pump motorL. Main gas pressure regulator

M. Fuel oil metering valve (not visible)N. Air damperO. Automatic gas valveP. Fuel oil cooling coilQ. Fuel oil fi lterR. Secondary gas manual shutoff valveS. Gas butterfl y valveT. Low media pressure switchU. Control panel V. Expansion tank pressure relief valve

(for nitrogen only) W. Overfl ow / vent pipe

PQ

TU

V

W

Page 19Figure 10. Location of components on RH side of HCS heater.

A. Expansion tankB. Expansion tank fi llerC. Sight gage shutoff valveD. Sight gageE. Low media level switchF. Heater end cover plateG. Outlet pressure gage port and valveH. Thermometer portI. Outlet from helical coilJ. Coil outlet thermocoupleK. Thermal fl uid return inletL. Valve No. 2 (purge)M. Valve No. 1 (strainer)

N. Valve No. 3 (expansion)O. Thermal fl uid return lineP. Thermal fl uid fi ll valve (used only on

early heaters)Q. StrainerR. Valve No. 4 (coil inlet)S. Flame scannerT. Burner fan motorU. Pilot gas pressure regulatorV. Circulating pumpW. Inlet pressure gage port and valveX. Low combustion air switchY. Shutoff valve, low media pressure switch

A B

C

DE

F

G

H

IJ

W

V

UT

S RQ P

O NM

L K

X

Y

Page 21

Figure 11. Wiring diagram.

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Page 23

Figure 13. Drain valve installed in strainer flange. (Wear chemical and heat resistant gloves as protection from hot oil.)

Operating mode

Valves on heater thermal fluid pipingValve No. 1 Valve No. 2 Valve No. 3 Valve No. 4

Run Open Closed Open OpenPurge Closed Open Open Open

Clean Strainer Closed Closed Closed Closed

Figure 16. Valve settings for operating modes.

Figure 15. Removing fuel pump coupling.

Figure 17. Suggested set points for High Media Temp. Controller.

Modulating Controller set point

High Temp. Controller set pointHCS Heater HC Heater

320 degrees F 370 degrees F 400 degrees F350 degrees F 400 degrees F 430 degrees F370 degrees F 420 degrees F 450 degrees F

(Normally 50 degrees F higer than set point on Modulating Controller

(Normally 80 degrees F higer than set point on Modulating Controller)

Figure 12. Fluid pressure gage installed in coil inlet pressure gage port.

Figure 14. Opening and closing valves.

Open when stem is rotated fully counter-clockwise.

Closed when stem is rotated fully clockwise.

Page 23

Figure 18 Close-up views of key components on HC (manifold) heater.

Manifold thermocouple Outlet thermocouple Modulating actuator

High fuel gas pressure switch

Low media pressure switch

Flame scanner

Pilot gas solenoid valve

Control transformer 120 Volts / 1 Phase / 60 Hz Main disconnect circuit breaker with keyed rod

Aux contacts, comb. air & circ pump motor controllers

Low media level switch

Low combustion air switch

Low fuel gas pressure switch High flue gas temperature switch

Ignition transformer

Main and auxiliary oil solenoid valves

Comb. air & circ pump motor breakers

HMT 1, BC 1, LML 1 relays

A B C

D E F

G H I

J K L

M N O

P Q R

Page 25

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Figure 19. Understanding proportional control (optimum heater size).

Figure 20. Understanding proportional control (oversized heater).

Page 25

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Figure 21. Understanding proportional control (undersized heater).

Figure 22. Proportional control . Figure 23. Proportional control with integral correction.

Figure 24. Proportional control with integral and derivative correction.

Page 27Figure 25. Lubrication requirements.

Index Name Fitting Lubricant FrequencyA Modulating actuator linkage (4 or 6 ball joints) General purpose oil monthly

B Valve No. 3 (expansion) Button head Resun 104 or 104 G monthly

C Valve No. 2 (purge) Button head Resun 104 or 104 G monthly

D Auxiliary side pump motor(HC series only)

Standard General purpose grease 3 months

E Auxiliary side pump(HC series only)

Standard High temperature lithium grease 1600 hours of operation

F Auxiliary valves(HC series only)

Button head Resun 104 or 104 G monthly

G Valve No. 1 (strainer) Button head Resun 104 or 104 G monthly

H Valve No. 4 (coil inlet) Standard General purpose grease monthly

I Circulating pump Button head High temperature lithium grease 1600 hours of operation (HCS)2800 hours of operation (HC)

J Circulating pump motor Standard General purpose grease 3 months

J

B C

DEFH GI E E D DFF

A. Linkage ball joints (4 or 6)

Button head fi tting Standard grease fi tting

Page 27

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TROUBLESHOOTING

GeneralThis information is intended for use by qualified technicians. The troubleshooting information assumes that the troubleshooter is familiar with operation of the heater as described earlier in this manual. Accordingly, Troubleshooting Table Appendix E and adjustments in this section do not provide detailed steps for operating the heater. Moreover, we assume that qualified technicians know how to use tools and test instruments that may be required to check and adjust the heater.

The information in the troubleshooting table covers the most common heater problems likely to be encountered. Because of the complexity of certain problems, you will probably find the remedies and adjustments in this manual easier to perform than oral instructions over the phone from our service personnel. So, if you encounter a heater problem, we highly recommend that you review the material in this manual and try to resolve the problem before calling our service department.

If you still can’t resolve the problem, call our service department (1-800-235-5200). Even if you are not able to solve the problem without our help, your efforts to do so before calling will pay off. You will gain familiarity with the product and be in a better position to describe the problem to our service personnel.

Make sure you know functions of control panel lights and switchesThe typical panel (Fig. 8) has a flame monitor, modulating controller, high media temperature controller plus several indicator lights and several manually controlled switches. Note: the term media means thermal fluid. Thermal fluid is commonly called hot oil.

Controls on the front of this panel allow the operator to start and run the heater. Knowing how these controls and indicator lights work provides the keys to troubleshooting the heater. This document describes each of these components. By reading these descriptions while examining the wiring diagram (Fig. 11) you should be able to get a clear understanding of how the heater works. The various components depicted on the wiring diagram are shown in Fig. 9, 10 and 18.

Don’t overlook the simple things The first thing to do when you find that an indicator light is not on when it should be on is to check its bulb. You would be amazed at how many service problems have been solved by replacing a burned-out bulb with a new one. Also make sure

that electrical power is turned on to all heater components that should be working. We often overlook the simple, obvious causes of problems and look for more complex answers.

Live circuits inside the control panelBe aware that certain heater control panels have electrical circuits that are not shut off by the rotary door-mounted handle. Panels that combine Heatec heater controls and Astec plant controls may include live circuits controlled by circuit breakers elsewhere in the plant. Consequently, shutting off the main breaker inside the panel does not remove all power to components within the panel.

Pay special attention to the limit circuit Most heater problems show up in the limit circuit. A problem in that circuit is indicated by one or more lights being off. So pay close attention to all the lights in the limit circuit. They are the ones with the clear lenses (Fig. 8). They should all be on during normal operation. Read the full description of this circuit under the heading LIMITS MADE indicator light.

Page 29

Understanding the wiring diagramThe wiring diagram Shown in Fig. 11 has been enhanced for easier understanding. Use the material shown in this diagram to get a general understanding of how things work. But go by what’s on your panel and shown in the wiring diagram furnished with your heater if you are trying to resolve a problem with your heater.

The type of wiring diagram we use (Fig. 11) is known as a ladder drawing. The drawing is divided into three segments, a left segment, a middle segment and a right segment. The power bus is represented as two thick lines that run from top to bottom of each segment. The line on the left represents the hot bus. The line on the right represents the neutral bus.

Each line on the left side has equally spaced numbers from top to bottom. These are known as rung numbers, as in rungs of a ladder. They divide the drawing into small zones that stretch from the hot bus to the neutral bus. Thus, these numbered zones help identify where things appear on the drawing.

Note that certain numbers appear at various bus terminal connections next to the neutral bus on the right side of each drawing segment. These denote that the relay coil connected to that terminal has contacts shown elsewhere. You can find those contacts by going to the zone indicated by the rung number.

Note also the small open circles, squares, and hex-shaped symbols. These denote certain terminals as explained in the legend on the drawing. These symbols appear at the end of certain lines (wires) to indicate that they are connected to terminals on components shown elsewhere on the drawing. This eliminates the need to draw a maze of lines that would complicate the drawing and be difficult to trace from one point to another.

As a further aid, the wiring diagram shows rectangles with words matching those on front panel labels. The black ones with white lettering are for all indicator lights. The open ones with black lettering are for switches.

Understanding the control panel (Fig. 8)The following paragraphs describe functions of components mounted on the control panel. The words set in all capital letters match the labels on the panel.

FIREYE FLAME MONITOR (Fig. 8)The Fireye flame monitor E110 is a microprocessor based burner management control system. It is included on Heatec HC and HCS heaters, which have ignited oil, gas and combination fuel burners. The monitor provides the proper burner sequencing, ignition and flame monitoring protection. In conjunction with limit and operating controls it sequences the burner/blower motor, ignition and fuel valves to provide for proper and safe burner operation. The control also provides current operating status and lockout information in the event of a safety shutdown. Its display panel shows up to 42 different messages related to the operating state of the heater.

Appendix A shows a logic flow diagram of the Fireye Flame Monitor E110. Thus, this diagram shows the sequence of events controlled by the monitor. In order to understand this diagram you will need to relate its terminal numbers to those shown in wiring diagram Fig. 11. Note that all numbers shown in square boxes refer to terminals on the Fireye Flame Monitor.

MANUAL RESET switch (Fig. 8)A switch for resetting the flame monitor. This switch is on the outside of the panel and duplicates the function of the switch actually on the flame monitor, which is mounted inside the control panel. This external switch eliminates the need to open the control panel to reset the monitor.

MODULATING CONTROLLER (Fig. 8) This unit is normally a Honeywell UDC 3300 Universal Digital Controller. It provides three functions:

• Burner modulation control

• Burner low-fire control

• Burner on/off control

Burner modulation control. This function of the UDC 3300 controller controls heating of the thermal fluid to maintain a temperature setting (known as set point or SP) that has been preset by the operator. It senses fluid temperature (known as a process variable or PV) from a thermocouple. It processes the output voltage of the thermocouple and sends control signals to Honeywell modulating actuator TZ4-1 (D, Fig. 5), which either increases or decreases the firing rate as required to maintain fluid temperature at set point. The difference between set point and PV is known as error.

The controller maintains the temperature within one or two degrees of set point when the heating system is in a steady state or maintenance mode. However, when starting up a cold system the burner fires at its maximum rate until the temperature of the thermal fluid (PV) reaches the preset proportional band (PB) of the modulating controller. The proportional band is the modulating range of the controller. While thermal fluid temperatures are within the proportional band, the controller causes small incremental changes in the burner firing rate (in proportion to the error) allowing its temperature to reach set point.

The proportional band (for an asphalt plant) is usually from 7-1/2 degrees below set point to 7-1/2 degrees above set point. Thus, when the set point is 320 degrees F, the controller causes the burner to modulate or vary proportionally while thermal fluid temperatures vary from 312.5 to 327.5 degrees F. Thermal fluid temperatures above 327.5 cause the controller to go to zero output, which sets the burner to its low-fire position. Thermal fluid temperatures below 312.5 cause the controller to fire the burner at its maximum rate. For further explanation of the UDC 3300 controller, please refer to Understanding Tune Functions of the UDC 3300 Controller earlier in this manual.

Page 29

Thermocouples. Heaters without manifolds have one duplex thermocouple (J, Fig. 10) installed near the outlet of the helical coil. The thermocouple has two pairs of leads. One pair is connected to the UDC3300 controller for temperature regulation. The other is connected to the UDC 2300 controller, which prevents temperature of the thermal fluid from exceeding its limits.

On heaters with manifolds, two duplex thermocouples are installed. Only one pair of leads from each thermocouple is used, leaving a spare set of leads. One thermocouple (B, Fig. 18) is installed near the outlet of the helical coil and is connected to the UDC 2300 controller which prevents the temperature of the thermal fluid from exceeding its limits. The other (A, Fig. 18) is installed in the manifold and is connected to the UDC 3300 controller for temperature regulation. Note: fluid temperature at the thermocouple in the manifold could be as much as 50 degrees (or more) lower than its temperature at the thermocouple in the outlet.

Honeywell modulating actuator TZ4-1 (D, Fig. 9). This unit controls the firing rate of the burner in response to signals it receives from the modulating controller. It controls the firing rate by moving mechanical linkage connected to the gas butterfly metering valve, the fuel oil metering valve and the air damper to either increase or decrease the firing rate. If linkage becomes loosened from operation it will lose its adjustment and the burner will not operate properly. This is a common problem.

The actuator has two cams that are activated when the heater is started up by the Fireye flame monitor. When startup is initiated the actuator goes to high fire purge, causing one cam to close a switch inside the actuator thereby confirming that the system is in high fire purge. Then, after a preset time, the actuator automatically goes to low fire purge and the other cam closes another switch inside the actuator thereby confirming that purge is complete and that the system is ready to light in low fire.

Burner low-fire control. This function of the UDC 3300 controller causes the burner to change from low-fire to high-fire when the temperature of the thermal fluid reaches a predetermined value known as A2S1 VAL (Alarm 2 Setpoint 1 Value). It is normally set manually at 200 degrees F. Thus, the burner will remain at low-fire until the thermal fluid temperature reaches 200 degrees F. At that point it goes to high fire and remains there until the temperature reaches the modulating range.

Burner on-off control. This function of the UDC 3300 controller shuts off the burner completely by shutting off its main fuel valve. This happens if system heat demand decreases, allowing thermal fluid temperature to reach a limit equal to the set point plus a predetermined value known as A1S1 VAL (Alarm 1 Setpoint 1 Value). This value is normally set manually at 20. It is known as a floating value since it creates a limit based on the set point. Thus, if its value is 20 and the set point is 320 degrees F, the limit is 340 degrees F

(the sum of 320 plus 20). After the thermal fluid cools down the controller initiates a new burner cycle. The amount of cool-down before the new cycle begins depends on a predetermined value known as AL HYST (Alarm Hysteresis). This is normally set at 3.9, which means a drop of 3.9 percent below set point.

HIGH MEDIA TEMP. CONTROLLER (Fig. 8)This unit is normally a Honeywell UDC 2300 Universal Digital Controller, Limit Control Model. It limits maximum temperature of thermal fluid to a set point (SP) value that the operator presets in the controller. (Do not confuse the set point of this controller with the set point of the UDC 3300.) The high media controller senses fluid temperature from a thermocouple (J, Fig. 10) in the outlet side of the helical coil. If the temperature of the thermal fluid exceeds preset limits (SP) the controller de-energizes the high media temperature relay, opening its contacts and shutting off the burner. The controller must be manually reset in order to restart the burner. The controller cannot be reset until the temperature of the thermal fluid has fallen below the set point value.

The preset temperature limit (SP) should always be set to a value higher than the modulating range of the burner. Otherwise, normal modulation of the burner may cause the burner to shut off prematurely. For example, if the set point is 320 degrees F and normal burner modulation allows the fluid temperature to reach 7-1/2 degrees above that point, be sure to set the maximum limit above 327.5 degrees F. (See Fig. 17 for suggested settings.)

Note: the maximum limit for a single line heater is not the same as the limit for a heater with a manifold. On single line heaters set the maximum limit to 370 degrees F. On heaters with manifolds set the limit to about 400 degrees F. Remember, the temperature settings in this example are typical and may need to be reset to different values in the field for actual operating conditions.

POWER ON indicator light (Fig. 8)This indicator light denotes the status of power to the control panel. The light is on when 120 Vac, single phase, 60 hertz power from the Heatec control transformer is connected to the terminal bus within the panel. When there is no power connected to the terminal bus the light is off. The light usually has a white lens.

HEAT DEMAND indicator light (Fig. 8)An indicator light that indicates the status of the burner control relay during normal operation. When the light is on the relay contacts are closed, which means that the relay is energized. When the light is off the relay contacts are open, which means that its coil is not energized. The coil is controlled by the Honeywell UDC 3300 Universal Digital Controller. The light has a blue lens. The light is on when the controller is calling for heat. It is off when the controller is not calling for heat.

LOW MEDIA LEVEL indicator light (Fig. 8)An indicator light that denotes the level of thermal fluid in the expansion tank during normal operation. It is electrically

Page 31

connected to the low media level relay, which is controlled by a float switch mounted in the expansion tank (K, Fig. 18).

When the light is on, the level of fluid in the expansion tank is within normal operating range and the level switch and relay contacts are closed. When the light is out, the level of fluid in the expansion tank is abnormally low and the switch and relay contacts are open.

The float switch in the tank is also part of the limit circuit and will shut down the heater when opened. Moreover, when it opens it also disables the circulating pump circuit. The switch automatically closes when the fluid level in the tank is restored to normal.

HIGH FUEL GAS PRESS. indicator light (Fig. 8)An indicator light that denotes the status of the high fuel gas pressure switch (D, Fig. 18) when the FUEL SELECTOR switch is set to GAS. When the light is on the fuel gas pressure is normal and the switch is closed. When the light is out the fuel gas pressure is too high and the switch is open. This switch is part of the limit circuit and will shut down the burner when open. The switch has a manual reset button.

LOW FUEL GAS PRESS. indicator light (Fig. 8)An indicator light that denotes the status of the low fuel gas pressure switch (E, Fig. 18) when the FUEL SELECTOR switch is set to GAS. When the light is on the fuel gas pressure is normal and the switch is closed. When the light is out the fuel gas pressure is too low and the switch is open. This switch is part of the limit circuit and will shut down the burner when open. The switch has a manual reset button.

HIGH MEDIA TEMP. indicator light (Fig. 8)An indicator light that denotes temperature status of the thermal fluid. It is electrically connected to contacts of the high media temperature relay, which is controlled by the high temperature controller UDC 2300.

When the light is on, temperature of the thermal fluid is within normal operating range. When the light is out, the temperature of the fluid has exceeded the preset limit of the controller. The relay contacts are also part of the limit circuit, which shuts down the burner when the contacts are opened. The controller must be reset after the thermal fluid has cooled down to within the operating range.

HIGH STACK TEMP. indicator light (Fig. 8)An indicator light that denotes temperature status of gas in the exhaust stack. It is electrically connected to the high flue gas stack temperature switch (C, Fig. 9) mounted in the exhaust stack. This switch is also known as a differential expansion temperature control.

When the light is on, temperature of the gas is within normal operating range and the switch contacts are closed. When the light is out, gas temperature has exceeded its factory setting of 1000 degrees F and the contacts are open.

The switch is also part of the limit circuit and will shut down the heater when the switch is opened. The switch must be manually reset, which requires removing its cover and pressing a reset button. (See warning that follows.)

CIRC. PUMP AUX. CONTACTS indicator light (Fig. 8)An indicator light that denotes the status of a set of auxiliary contacts (N, Fig. 18) on the motor controller that connects electrical power to the motor of the fluid circulating pump. When the indicator light is on electrical power is connected to the pump motor. When the light is off the contacts are open because electrical power is not connected to the motor.

The contacts are also part of the limit circuit and will shut down the heater when opened. The contacts automatically close when power is restored to the motor.

LOW MEDIA PRESS. (OR FLOW) indicator light (Fig. 8)An indicator light that denotes pressure/flow status of thermal fluid in the helical coil. It is controlled by a switch (G, Fig. 18) that detects low media pressure near the inlet of the helical coil. When the indicator light is off the switch is open indicating that the pressure of thermal fluid is too low. When the light is on the switch is closed indicating that there is sufficient pressure.

Inadequate pressure/flow of thermal fluid is probably the most common cause of heater malfunctions. A clogged strainer is the most common cause of inadequate flow of thermal fluid.

Low media pressure switch (T, Fig. 9). Although this switch is sometimes called a flow switch it actually senses pressure. It detects abnormally low pressure of thermal fluid in the helical coil circuit. And because low pressure in this particular circuit results in low flow, the switch serves as a low flow switch.

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Page 31

When the switch opens due to abnormally low pressure/flow the heater will shut down. Moreover, the heater cannot be restarted until adequate pressure/flow is restored.

There is no manual reset for this switch. It automatically closes when adequate pressure/flow is restored.

Strainer. The strainer (Q, Fig. 10) traps trash in thermal fluid to prevent damage to pumps and valves. It must be cleaned periodically to prevent buildup of trash. Excessive buildup of trash in the strainer reduces flow of thermal fluid through the helical coil and activates the low media flow switch.

COMB. AIR AUX. CONTACTS indicator light (Fig. 8)An indicator light that denotes the status of a set of auxiliary contacts (N, Fig. 18) on the motor controller that connects electrical power to the burner fan motor. When the indicator light is on electrical power is connected to the fan motor. When the light is off the contacts are open because electrical power is not connected to the motor.

The contacts are also part of the limit circuit and will shut down the heater when opened. The contacts automatically close when power is restored to the motor.

LIMITS MADE indicator light (Fig. 8)An indicator light that denotes the status of a limit circuit, which has several switches connected in series with each other (Fig. 11). This circuit is also connected to the Fireye flame monitor so that its current flows through the Flame monitor and through the solenoids of the fuel control valves.

When this light is on all of the switches in the limit circuit are closed and operating conditions are normal.

When this light is off one or more of the switches is open because of an abnormal operating condition. An open switch disconnects current flowing through the solenoids of the fuel control valves. This closes the fuel valves, shutting off fuel to the burner. Consequently, the flame monitor will display the message: FLAME FAILURE 3 TO P INTERLOCK OPEN. The flame monitor must be manually reset after the abnormal condition has been cleared.

A separate indicator light is also provided for each switch in the limit circuit, except for the low combustion air switch, which is the last switch in the series. (These lights are described earlier in this document.) The indicator lights identify the status of each individual limit switch. All indicator lights in the limit circuit have clear lenses, except for the LIMITS MADE light, which has a green lens.

The following components are in the limit circuit and are connected in series with each other in the sequence listed here:

1. Low media level switch (K, Fig. 18)

2. High fuel gas pressure switch (D, Fig. 18)

3. Low fuel gas pressure switch (E, Fig. 18)

4. High media temperature relay (R, Fig. 18)

5. High flue gas stack temperature switch (F, Fig. 18)

6. Motor contactor auxiliary contacts for circulation pump motor (N, Fig. 18)

7. Low media press switch (G, Fig. 18)

8. Motor contactor auxiliary contacts for combustion air motor (N, Fig. 18)

9. Low combustion air pressure (differential) switch (H, Fig. 18)

If any one of these switches is opened by an abnormal condition its corresponding light will go out. Moreover, all lights in the series downstream or after that switch will go out. The first light out in that sequence denotes the abnormal condition that initiated the shutdown.

Note, because the low combustion air switch is the last switch in the series it does not have a separate indicator light (on some heaters). It is connected immediately ahead of the LIMITS MADE light. Thus, if the low combustion air switch opens due to abnormally low air pressure, the LIMITS MADE light will go off. You will know that the low combustion air switch is the reason for the light going out if all other lights are on.

Note that some of the limit switches automatically reset themselves after an abnormal condition has cleared. Accordingly, it is not always possible to go by the first light you find off after a period of time has lapsed after a shutdown. If one of these circuits causes a shutdown due to an abnormal condition that subsequently clears itself, you might find its light on. This could mislead you unless you actually observed the light go off before it came back on. The following circuits automatically reset themselves after an abnormal condition de-activates them, so make sure they did not cause the abnormal condition even though their lights are not the first off. One way to do this is to press MANUAL RESET and observe the limit indicator lights for about 10 seconds. Note which one went off first during this time.

1. Low media level2. Low media pressure3. Low combustion air pressure (differential) switch

IGNITION ON indicator light (Fig. 8)This indicator light denotes the status of two ignition circuits: ignition spark transformer (I, Fig. 18) and pilot gas solenoid valve (M, Fig. 18). The light has an amber lens. When the light is on, power is connected to the ignition spark voltage transformer and to the pilot gas solenoid valve. As a result the pilot valve opens and high voltage is generated in the secondary winding of the spark ignition transformer. The high voltage produces a spark across the gaps in the points of the igniter to ignite the pilot gas. When the light is off, power is not connected to the transformer or solenoid valve. Hence, there is no spark and the pilot gas is off. Power to the circuit is controlled by the Fireye flame monitor.

GAS VALVE ON indicator light (Fig. 8)This indicator light denotes the status of the main gas shutoff valve, which is a solenoid operated valve. When the light is

Page 33

on, the valve is open. When the light is off, the valve is closed. This light has an amber lens.

OIL VALVE ON indicator light (Fig. 8)This indicator light denotes the status of the main oil valve(G, Fig. 9) and the auxiliary oil valve (J, Fig. 9). Both are solenoid-operated valves. When the light is on, the valves are open. When the light is off, the valves are closed. This light has an amber lens.

HEATER ALARM indicator light (Fig. 8)This indicator light denotes the status of the heater alarm system. When the indicator light is on the heater is in an alarm state. The light has a red lens. The alarm is controlled by the flame monitor, which turns on the alarm when it detects a variety of abnormal conditions. The monitor displays one of several messages to report the condition that caused the alarm.

BLOWER ON indicator light (Fig. 8)This indicator light denotes the status of the combustion air blower. When the indicator light is on electrical power is connected to the blower motor controller. When the light is off, no power is connected to the controller. The light has a blue lens. Power to the controller is controlled by the flame monitor.

LOW FIRE HOLD-NORMAL switch (Fig. 8)This is a manually controlled switch for holding the burner in low fire to prevent it from going to a higher firing rate. This is normally done when starting the heater cold to allow water vapors to clear out of the heater. When set to NORMAL the burner controller resumes normal operation where it can fully modulate the burner between low and high fire. The switch is connected to the Honeywell UDC 3300 Universal Digital Controller.

CIRC. PUMP OFF-ON switch (Fig. 8)This is a manually controlled switch for applying/removing power to/from the circulating pump motor. This switch must be on for the heater to operate. The switch is in series with the low media level relay and the motor controller breaker auxiliary switch, both of which must be closed for power to reach the motor.

HEATER CONTROL OFF-ON switch (Fig. 8)This is a manually controlled switch for turning the heater on and off. It must be on for the heater to operate.

HEATER ALARM OFF-ON switch (Fig. 8)This switch is provided in the horn circuit so that the horn can be switched off until the problem that set off the alarm can be cleared. It should be turned back on after the problem is cleared.

HEATER ALARM horn (Fig. 8)This horn denotes the status of the heater alarm system. When the horn is sounding the heater is in an alarm state. A switch is provided in the horn circuit so that the horn can be switched off. The alarm is controlled by the flame monitor, which turns on the alarm when it detects a variety of abnormal conditions. The monitor displays one of several messages to report the condition that caused the alarm.

GAS-OIL switch (Fig. 8)This is a manually controlled switch for selecting either gas or oil as a fuel source to operate the heater. Setting the switch to OIL allows the flame monitor to energize and open the two solenoid valves (main and auxiliary) in the fuel oil supply line. This setting prevents the main gas valve from energizing.

Setting the switch to GAS allows the flame monitor to energize and open the automatic gas valve. This setting prevents the two fuel oil shutoff valves from energizing.

AUX. PUMP OFF-ON switch (Fig. 8)This is a manually controlled switch for applying/removing power to/from an auxiliary pump motor. This switch must be on to pump thermal fluid through the piping circuit connected to the pump. The switch is in series with the motor controller breaker auxiliary switch, which must be closed for power to reach the motor.

Note: there may be more than one of these switches on the control panel, depending upon the number of independent thermal fluid circuits used. When there is more than one, the switches are marked #1, #2, #3, etc. to identify different independent circuits. Only heaters with manifolds (Fig. 1) have auxiliary pumps to circulate thermal fluid through independent piping circuits, each with its own pump. These circuits operate independently of the thermal fluid circuit that circulates thermal fluid through the coil of the heater. (The thermal fluid of heaters without manifolds is circulated through all piping circuits by the same pump that circulates the fluid through the heater.)

Rotary door-mounted operating handle (Fig. 8)Use this handle to open the control panel. Do not open the door unless you are a qualified technician familiar with the hazards of electricity.

As a safety feature the handle disconnects incoming electric power from the control panel when the panel is opened. A keyed rod from the main circuit breaker (Q, Fig. 18) inside the panel engages a slot on the back of the handle. The rod switches the breaker on and off as the handle is rotated. The handle is marked to indicate its functions.

Be aware that certain heater control panels have electrical circuits that are not shut off by the rotary door-mounted handle. Panels that combine Heatec heater controls and Astec plant controls may include live circuits controlled by circuit breakers elsewhere in the plant. Consequently, shutting off the main breaker inside the panel does not remove all power to components within the panel.

A screw on the left side of the handle allows you to open the panel without shutting off the main circuit breaker. To do so, use a screwdriver to turn the screw about 1/4 turn counter-clockwise and then rotate the handle to open the door. The purpose of this feature is to allow you to open the panel without shutting down the heater. Use extra caution when working inside the panel while the power is on. Always use a voltage tester to make sure there is no voltage on terminals or bare wires you may touch.

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Appendix A

Page 35

Appendix B, page 1.

Programming Honeywell UDC 3300 (Modulating Controller)

for Heatec HC and HCS heatersGroup Prompt

(SET UP button)Function Prompt

(FUNCTION button)

Value or

Selection(up / down arrows)

Group Prompt Function Prompt

Value or Selection

TUNING PROP BD 2.0 ALGORTHM CONT ALG PID A

or GAIN TIMER DISABL

or GAINVALn Read Only PERIOD

RATE MIN 0.08 START

RSET MIN LDISP

or RSET RPM 3.00 INP ALG1

or MAN RSET MATH K

PROPBD2 CALC HI

or GAIN 2 CALC LO

RATE2MIN ALG1 INA

RSET2MIN ALG1 INB

or RSET2RPM ALG1 INC

CYC SEC PCO SEL

or CYC SX3 PCT CO

SECURITY 0 ATM PRES

LOCKOUT CALIB

AUTO MAN OUT ALG OUT ALG CURRNT

SP SEL 4-20 RNG

RUN HOLD OUT2 ALG

RLYSTATE

SPRAMP SPRAMP DISABL RLY TYPE

TIME MIN

FINAL SP INPUT 1 IN1 TYPE J TC L

SP RATE DISABL XMITTER1

EU/HR UP IN1 HI 770.0

EU/HR DN IN1 LO 20.00

SP PROG DISABL RATIO 1 1.000

BIAS IN1 0.0

ACCUTUNE FUZZY DISABL FILTER 1 1

ACCUTUNE DISABL BURNOUT1 UP

AT ERROR EMMISIV1

INPUT 2 IN2 TYPE

XMITTER2

IN2 HI

IN2 LO

RATIO 2

BIAS IN2

FILTER 2

BURNOUT2

EMMISIV2

Page 35

Appendix B, page 2.

Programming Honeywell UDC 3300 (Modulating Controller)

for Heatec HC and HCS heatersGroup Prompt Function

PromptValue or Selection


Value or Selection

CONTROL PV SOURCE COM ComSTATE DISABL

or PID SETS 1 ONLY ComADDR

SW VALUE SHEDTIME

LSP’S 1 ONLY PARITY

RSP SRC BAUD

or AUTOBIAS DUPLEX

SP TRACK NONE TX DELAY

or PWR MODE A LSP SHEDMODE

PWR OUT SHEDSP

SP HiLIM 500.0 UNITS

or SP LoLIM 20.00 CSP RATO

ACTION REVRSE CSP BIAS

or OUT RATE DISABL LOOPBACK

PCT/M UP

or PCT/M DN ALARMS A1S1 VAL 20.0

OUTHiLIM 100.0 A1S2 VAL

OUTLoLIM 0.0 A2S1 VAL 200.0

I Hi LIM 100.0 A2S2 VAL

I Lo LIM 0.0 A1S1TYPE DEV

DROPOFF 0.0 A1S2TYPE NONE

DEADBAND A2S1TYPE INP1

OUT HYST A2S2TYPE NONE

FAILMODE NO LAT A1S1 HL HI

FAILSAFE 0.0 A1S1 EV

MAN OUT 0.0 A1S2 HL

AUTO OUT 0.0 A1S2 EV

PBorGAIN PB PCT A2S1 HL LO

MINorRPM RPM A2S1 EV

A2S2 HL

OPTIONS AUX OUT A2S2 EV

4mA VAL AL HYST 3.9

20mA VAL ALM OUT1 NO LAT

DIG IN 1 BLOCK

DIG1 COM

DIG IN 2 DISPLAY DECIMAL XXXX

DIG2 COM TEMPUNIT F

PWR FREQ 60 HZ

RATIO 2

LANGUAGE ENGLIS

Page 37

Programming Honeywell UDC 2300 (High Media Temp. Controller)

for Heatec HC and HCS heatersGroup Prompt

(SET UP button)Function Prompt

(FUNCTION button)

Value or Selection

(up / down arrows)


Value or Selection

LOCK SECUR 0 COM ComSTA DISABL

LOCK CAL ComADR

SHDTIM

LIMIT LO or HI HIGH PARITY

POWRUP NORM BAUD

SP MAX 500.0 TX DLY

SP MIN 20.00 UNITS

DISPLY PROC LOOPBK

INPUT 1 DECIMAL 8888 ALARMS A1S1 VA

UNITS F A1S2 VA

IN1TYP J L A2S1 VA

XMITR1 A2S2 VA

IN1 HI 770.0 A1S1TY NONE

IN1 LO 20.00 A1S2TY NONE

BIAS 1 0.0 A2S1TY NONE

FILTR1 1 A2S2TY NONE

BRNOUT UP A1S1 HL

EMIS A1S2 HL

FREQ 60 A2S1 HL

DISPLY A2S2 HL

AL HYST 0.1

OPTIONS AUXOUT ALARM1

0 PCT BLOCK DIS

100 PCT

EXT RST

Appendix C.

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Appendix DMAINTENANCE SCHEDULE

REQUIREMENT

WEE

KLY

MON

THLY

QUAR

TERL

Y

YEAR

LY

Check for proper level of thermal fluid. Sight gauge on expansion tank should show at least 3 inches. X

Clean ultraviolet flame detector lens. X

Check intake area of blower to make sure it is not blocked by foreign material and is free from buildup of dirt. X

Check flame to ensure burner shows no symptoms of being in need of tuning. (Refer to material under heading entitled How to Recognize An Out-of-Tune Burner.) X

During normal operation check all pressure gauges and thermometers on heater for values as indicated in Figure 7. X

Check all operating and limit controls and settings to make sure they are set properly and are working properly. X

Check strainer to ensure it is not dirty. X

Check heater and piping to ensure there are no leaks of thermal fluid or asphalt cement. X

Check heater to ensure there is no structural damage to heater shell, end plates, etc. or signs of over heating. X

Check pilot assembly to make sure spark gap is 1/8 to 3/16-inch. X

Check burner control linkage to make sure it is not binding or loose. X

Have exhaust stack gases analyzed and have burner tuned by a specialist X

Have thermal fluid analyzed to ensure it is not degraded. X

Lubricate heater according to requirements indicated in Figure 25. Per Figure 25

Page 39

PROBLEM PROBABLE CAUSE REMEDY

Heater will not start. Flame monitor shows message 3–P INTLK OPEN.

One of nine switches in limit circuit is open.

See discussion of LIMITS MADE indicator light.

Heater will not start. Flame monitor shows message LOCK OUT PTFI–FLAME FAIL (PTFI means Pilot Trial For Ignition)

1. Bad flame scanner.

2. Igniter improperly set.

3. Bad ignition transformer.

4. Bad ignition wire.

5. Bad pilot solenoid

6. Pilot gas regulator improperly set.

7. Bad amplifier card in flame monitor.

1. Check the flame scanner per instructions in MAINTENANCE and replace it if defective.

2. Reset per manual on Power Flame burner.

3. Check for 120 vac at primary. If ok check ignition wire for break. If ok check for spark. If no spark replace transformer.

4. Check wire for break. Replace if broken.

5. Check for click when energized. If no click check for 120 vac at solenoid terminals. Replace solenoid if there is no click when voltage is applied.

6. Check regulator and reset if necessary per instructions in MAINTENANCE.

7. Replace card.

Low media flow/pressure indicator light off.

1. Low media pressure switch (G, Fig. 18) out of adjustment.

2. Strainer clogged.

3. Level of media (thermal fluid) in expansion tank is too low.

4. Air in circulating pump.

1. Re-adjust low media pressure switch per instructions in MAINTENANCE.

2. Remove and clean strainer.

3. Check sight gauge on expansion tank. Confirm that sight gauge is correct by using measuring stick through top of tank.

4. Bleed air from pump per instructions in MAINTENANCE.

Low combustion air (limits made indicator light is off, but all other lights in limit circuit are on.)

1. Line to low combustion air switch (H, Fig. 18) is clogged.

2. Street elbow in low combustion air switch is clogged.

3. Fan blades of combustion air blower clogged with dust.

4. Low combustion air switch (H, Fig. 18) out of adjustment.

1. Disconnect air line and blow compressed air through the line.

2. Remove cover with burner sight glass. Remove street elbow and blow compressed air through it.

3. Clean blades to remove dust.

4. Readjust low combustion air switch per instructions in MAINTENANCE.

High media temperature indicator light is off.

1. Strainer is clogged.

2. Maximum temperature setting of UDC2300 is too low.

3. Inadequate flow of thermal fluid in system piping.


2. Re-set maximum temperature in UDC2300 to a temperature 80 degrees (min) higher than set point on UDC 3300. Press MANUAL RESET to clear alarm.

3. Check for closed or stuck valve in system piping.

Appendix E. Troubleshooting Table (Page 1 of 2)

Page 39

Appendix E. Troubleshooting Table (Page 2 of 2)

PROBLEM PROBABLE CAUSE REMEDY

High flue gas stack temperature indicator light is off.

1. High flue gas stack switch is tripped.

2. Strainer is clogged.

3. Helical coil in heater is coated with soot.

4. Inadequate flow of thermal fluid in system piping.

1. Remove cover from switch and reset switch.


3. Remove end cover of heater and clean coil per instructions in MAINTENANCE.

4. Check for closed or stuck valve in system piping.

Low media level indicator light is off.

1. Level of media (thermal fluid) in expansion is too low.

2. Low media level switch (K, Fig. 18) in expansion tank is malfunctioning.

1. Add thermal fluid to expansion tank. Also check piping to ensure there are no leaking connections.

2. Check low media level switch for proper operation per instructions in MAINTENANCE.

Media level sight gage does not accurately indicate fluid level in expansion tank.

1. Two valves on sight gauge not open.

2. Sludge in expansion tank.

1. Open both valves on sight gauge. Use measuring stick through tank filler pipe to confirm accuracy of gauge.

2. Clean sludge from expansion tank per instructions in MAINTENANCE.

Burner does not modulate. 1. Low fire hold switch in HOLD position.

2. Dip switches of modulating actuator TZ4-1 (C, Fig. 18) not set properly.

3. Low fire hold temperature of UDC3300 is set too high.

4. Defective power transformer in modulating actuator TZ4-1.

5. Defective resistor board in modulating actuator TZ4-1.

6. Defective motor in modulating actuator TZ4-1

1. Set switch to NORMAL position.

2. Re-set dip switches according to settings shown on wiring drawing. Note: use ball point pen to make sure switches are fully depressed!

3. Reset low fire hold temperature of UDC3300 to a lower temperature.

4. Check the transformer in the actuator and replace it if defective per instructions in MAINTENANCE.

5. Check the resistor board in the actuator and replace if defective per instructions in MAINTENANCE.

6. Check the motor in the actuator and replace if defective per instructions in MAINTENANCE.

Fuel oil pressure low or erratic. Damaged fuel pump drive coupling.

Remove blower and coupling, inspect spline for damage and slippage. Replace if damaged.

RESERVED FOR NEW INFORMATION

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Typical HMA plant with single-circuit HCS heater

Typical HMA plant with multiple-circuit HC heater

HEATEC, INC. 5200 WILSON RD, CHATTANOOGA, TN 37410 • PHONES 423-821-5200 • 1-800-235-5200 • WWW.HEATEC.COM • E-MAIL: [email protected]

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Publication 9-02-088 November 2002

HELICAL COIL · PDF fileHeatec helical coil heaters used in the Hot Mix Asphalt industry. ......

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Transcript of HELICAL COIL · PDF fileHeatec helical coil heaters used in the Hot Mix Asphalt industry. ......