RV Furnaces. Factory Information 676 Broadway Dayton, Tennessee 37321 Website: E-mail address:...
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Transcript of RV Furnaces. Factory Information 676 Broadway Dayton, Tennessee 37321 Website: E-mail address:...
RVFurnaces
Factory Information
676 Broadway
Dayton, Tennessee 37321
Website: www.rvcomfort.com
E-mail address: [email protected]
Factory Support Phone Numbers
Phone: 423 775-2131
Fax: 423 775-7015
Business Hours: 8 AM to 5 PM Eastern Time
Factory Technical Service Extension 7102 Service Manager
– Ronnie Ellison ext. 7007
Assistant Service Manager
– Louie Richard ext. 7005
Factory Customer Service Extension 7101 Customer Service Manager
– Sheila Cheek ext. 7016
Customer Service– Vicki May ext. 6372– Linda Welch ext. 6373– Jennifer Yawn ext. 6371
Furnace ModelIdentification
NT Lightweight Series Furnace
NT16/20 SQ– Side duct discharge.
NT Series Furnace
NT16/20 SEQ– Direct discharge
NT Heavyweight Series Furnace
NT30/34SP NT40
– Side and bottom duct discharge.
Park Model Furnaces(120 VAC)
P40– Side and bottom duct discharge.– Can be field converted to natural gas.– Same dimensions as NT series furnace
SF Series Furnaces
Rear & Front Gas
SF 20/25/30/35/42Q– Rear gas connection
• Service through outside door application.• Front, bottom, top & side duct discharge.
SF20/25/30/35/42FQ– Front gas connection
• Service from inside coach.• Front, bottom, top & side duct discharge.
Vertical Mount Furnaces
SFV 20/25/30/35/42Q– Rear gas connection
• Service through outside door application.• Front, bottom, top & side duct discharge.
SFV 20/25/30/35/42FQ – Front gas connection
• Service from inside coach.• Front, bottom, top & side duct discharge.
SH Series Furnace SH35/42 SH35/42 F
– Front & Rear gas connection.
– Front, bottom, top & side duct discharge.
– 9 ¼ inches H x 17 W inches x 20 inches D
SHD-2542 Furnace
– Dual Rate 25,000 & 42,000 BTU
– Front, bottom, top & side duct discharge
Tools & Equipment Required
Equipment
Volt-Ohm Meter
Manometer (calibrate monthly with U-tube)
Leak Check Solution
Assorted Hand Tools
Fenwal Module Board Tester---Part # 641511
Furnace Requirements
Gas Pressure
– 11 inches W.C. Minimum
– 14 inches W.C. Maximum
• W.C. water column
• Test with at least half of the appliances operating.
Voltage
– 10.5 Volts DC minimum
– 13.5 Volts DC maximum
Pressure Drop Test
– Install pressure gauge into gas
system
– Use leak check solution on fitting
– Eight (8) inches W.C. for three
(3) minutes
Furnace Components
Wire Connections
Four wires are used for connections.– Red 12 VDC positive.– Yellow 12 VDC
negative.– Blue thermostat
positive +.– Blue thermostat return
voltage.
Thermostat
– Bi-metal thermostat shown.
– Device used to control operation of furnace by reacting to ambient temperature.
On/Off Switch
– Device used to
control power to the
module board.
Fan Control Module Board Information
– Rewire kits available to
update non fan control MB furnace to fan control MB.
– Backwards compatibility with 520741 non fan control module board.
Fan Control Module Board Update
– On model SF20Q starting serial number 133900000 a smaller dimension fan control module board was introduced.
– Has the same operation as a 520820
Limit Switch
– Device used as a safety overheat switch. Normally closed switch.
– NOTE: sail switch may be before limit switch in some models.
Sail Switch
– Safety device that proves air flow.
– Normally open switch.
Furnace Motor
– Double shafted provides both room and combustion air.
12VDC motor. Built-in thermal overload protection.
Gas Valve
Controls and regulates gas flow to appliance
Furnace Orifice
– Meters gas flow.
– Drill size matches to BTU rate of furnace.
Furnace Burners
– A fuel burning device that supports combustion.
Ribbon
Tube
Punch Port
Electrodes
– Conductor of ignition source.
– Local or remote flame rectification.
LocalRemote
Flame senseSpark
Ground
1/8 inch spark gap
SF Electrode & Wire Assembly
– Local flame sense.
1/8 inch spark gap between burner
Furnace Sequence of Operation
– Understanding the sequence of operation makes diagnosis quick and accurate.
Sequence of Operation
– Thermostat calls for heat.
– Contacts close.
Sequence of Operation
– Current flows through
the ON/OFF switch
Voltage in from thermostat. Blue
wire
Voltage out to module board
Power terminal. Blue wire
Wire Connections to Fan Control Module Board
Red power & blue thermostat wire
Sequence of Operation
Power to module board Checks for proper
voltage Power to sail
switch/limit switch circuit
Sequence of Operation
Checks sail switch circuit
If circuit completed motor will not start– Sail switch is closed or
bypassed– Relay will have a
buzzing sound
Sequence of Operation
Module board checks for power to return from sail switch/limit switch circuit proving sufficient air flow to support combustion– If no power returns
blower shuts off in 30 seconds
Wire Connections to Fan Control Module Board
Blue return wire from limit or sail
switch
Sequence of Operation
Power to module board terminal within 15 seconds
Motor will start
Red wire connects to blower output on
module board
Black wire to ground terminal block
Wire Connections to Fan Control Module Board
Yellow ground wire
Red power & blue thermostat wire Red wire voltage out to motor
Sequence of Operation
If power returns from sail switch/limit switch circuit– 10-15 second purge
cycle
Sequence of Operation
Power through sail switch/limit switch circuit
Wire Connections to Fan Control Module Board
Red wire Voltage in from Limit or Sail
switch
Yellow ground wire
Blue return wire from limit or sail
switch
Red power & blue thermostat wire Red wire voltage out to motor
Sequence of Operation
– Module board simultaneously:
• Provides spark to electrode
• Provides voltage to gas valve
• Checks for flame rectification
Yellow wire to ground terminal
block
Sequence of Operation
If flame is detected– Shuts off spark to
electrode– Keeps gas valve
powered– Monitors flame
Sequence of Operation
If flame is not detected after 7 second trial for ignition period– Shuts off ignition– Goes through purge
cycle– 2nd trial for ignition– Goes through purge
cycle– 3rd trial for ignition
Sequence of Operation
If flame is not detected after 3 TFI– Lockout occurs– Blower shuts off after 3
minutes – Thermostat must be
manually reset
Furnace Troubleshooting
Understand the complaint.– When does the issue occur?
• Hot or cold outside ambient?• Start of cycle or mid-cycle?
Always turn off gas supply when checking initial sequence of operation!
AMP DRAW TEST
Red motor lead is removed from module board motor terminal.
MOTOR AMPERAGE CHART
Gas Valve Troubleshooting
Gas Test Port
30-50Ohms on each
solenoid .48 Amps
Gas pressure regulator 10.5 inches output Redundant protection
SF burner with electrode setting
Troubleshooting Module Board
It is recommended to use the module board tester.
The module board will monitor the sail switch circuit upon a call for heat if the sail switch is closed the motor will not operate.
Plastic combustion air housing (SF models)Sail switch mounted to
Plastic room air housing. If closed no
motor operation.
Troubleshooting Module Board
If the sail switch does not close or the limit switch is open the furnace will shut down blower operation with no TFI (trial for ignition) within 30 seconds.
Troubleshooting Module Board
If during the heating cycle, the limit switch circuit opens and remains open for five (5) minutes, the module board will go into LOCKOUT and shut down blower operation.
Module board constantly checks for a minimum of 9.5 VDC. If not available the module board will go into STANDBY mode until voltage is available.
Troubleshooting Tips
– Check burner for proper flame. • Flame should be blue and have definition
• Gas pressure
• Restriction in combustion chamber
Installation Troubleshooting
Always start by reviewing the installation.
Installation issues can cause operation issues with the furnace.
Installation Troubleshooting
– Check furnace for proper mounting and
furnace is secured properly.
– Check all gas connections with leak check
solution.
Installation Troubleshooting Check furnace venting
– Vents not blocked
– Vent tubes have proper overlap
Check for soot on vent. If soot is present check the
following
– Check combustion chamber integrity
– Check all gaskets
Installation requirements of vent cap & intake tube ½” minimum overlap
on intake tube
1 ¼” minimum overlap on exhaust
Refer to Installation Manual for
correct intake tube
SF vent cap
Silicone seal around perimeter of vent cap
NT vent cap
Silicone seal around
perimeter
Vent screw secured
Furnace Installation Checks
Return Air
Ducting
Clearances to Combustibles
• Refer to the furnace installation manual for each furnace model’s requirements.
Return Air Installation Checks
Verify return air of minimum of 55 sq. inches.
Total free unobstructed return air to the furnace.
– Measure opening and reduce square inches by restriction percentage of grille.
Insufficient return air will cause the furnace to overheat and cycle on limit.
Return Air review
The following pictures provide information on return air configurations.
Installation Checks Return air
Measure open area of grille.
Furnace cannot receive return air
when door is closed.
Ducting Installation Checks
Refer to the Installation manual for the minimum ducted square inches for each model.
Verify duct connections are tight on the furnace.
Ducts terminating in a dead air space with no means for return air can not be counted in the required duct area.
Ducting
In RV manufacturing several styles of duct work are used.
In-floor, side discharge using flex hose.
– The following illustrations will show different configurations.
Installation Checks Ducting
Avoid making sharp turns in the duct system. Each 90 degree adds 10 feet of hose.
Vertical installation. Ducts are mashed and
restricted.
2” Duct
Ducts 2 inches in diameter or smaller can not be counted in the required duct area.
Duct pulled tight not collapsed
Duct pulled tight & not collapsed
Excess hose inside cabinet
Return air grille minimum 18”
from heat duct
Plumbing and Electrical Components Can Crush Duct
Duct crushed by plumbing
Duct pinched
as it passes through
floor
Bottom Duct Installation
Verify unit is installed properly over cut out in floor. Correct if necessary.
Use gasket to seal between unit and floor.
NT knock out dimension 3 ¼ inches x10 inches. SF knock out dimension 4 inches x 14 inches.
In-floor Plenum
Maintain minimum open duct area throughout entire duct system including register
Duct extending into plenum too far
Floor RegisterRug or obstruction
over floor register can cause limit to cycle.
Closeable register not recommended
Installation Clearances Verify installation of furnace per installation
manual.
Check and verify the following before installation.
These instructions pertain to installing a new or replacement furnace.
Clearances to Combustibles
Maintain and adhere to minimum clearances from the furnace cabinet to combustibles per the furnace installation manual for each furnace.
Location Select a location
out of the way of wires, pipes, that may interfere with installation.
Clearance Required Opening
An opening must be provided in the interior of the cabinetry directly in front of the furnace.
Clearance Furnace Removal
The opening must allow for free, unobstructed removal of the furnace.
Serial Number information
Serial number information.– 00020449D– 00= year 2000– 02= 2ND week– 04449D serial
with a deviation listed
When Submitting a Warranty Claim Serial Data Plate
– Model number– Serial number– Date of purchase
– Include this information on warranty claims
Suburban Furnace Warranty
Two years parts and labor limited warranty.
3rd through 5th year limited warranty on the heat exchanger (no labor).
Flat rate time allowance at shop rate.
One year limited warranty on all replacement module boards
Suburban Furnace Warranty
Parts that need to be returned with warranty claim– Module boards, motors, gas valves, combustion
chambers.– Warranty parts will have a UPS return tag when
shipped from Suburban. This will cover return freight cost.
Warranty Information
Always use GENUINE Suburban factory authorized parts.
Do not need to be recommended service agency to perform warranty work.
After Market Bug Screens
Do not install SCREENS
over the vent for any reason.
Screens will become restricted, and can cause unsafe furnace operation.
Not recommended
Furnace Information
We have just discussed furnaces please remember that when the appliance is installed into a RV it becomes a heating system.
Not just a furnace.
Questions?