Service Basic Hd-c2

8/2/2019 Service Basic Hd-c2

1/23C20

Motor and pump Basic training HD / HDS

Pressure and flow control, manual with overflow valve

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2/23C21

Basic training HD / HDS Motor and pump

Pressure and flow control, manual with overflow valve

1 High-pressure outlet

2 Injector

3 Rotary knob

4 Regulating spindle5 Pressure valve

6 Cylinder head

7 Piston

8 Suction valve

9 Water inlet with strainer

10 Suction chamber

11 Pressure chamber

12 Connecting channel

13 Piston

14 Control chamber

15 Spring

16 Overflow valve spindle

1. Manual pressure and flow control byturning rotary knob

When the handgun is opened, the entire pumpcapacity flows through the injector (2) to the

high-pressure outlet (1).

As a result of the action of the injector (2), (seepage D2), the pressure in the control chamber(14) is lower than in the pressure chamber (11).This means that the spindle (16) in the overflowvalve remains in the upper position and closesoff the path between the pressure chamber (11)and the suction chamber (10).

By turning the rotary knob (3) to move theregulating spindle (4) downwards, the overflow

valve can be opened in a continuous movement.A part of the pump capacity then flows from thepressure chamber (11) into the suction chamber(10) and the operating pressure and flow ratedrop to the amount that has been set by turningthe knob.

2. When the handgun is closed

When the handgun is closed, no water flowsthrough the injector (2). The pressure chamber(11) and the control chamber (14) are linked by

a connecting channel (12) and the pressure inboth areas are the same. As the surface of thepiston (13) in the control chamber (14) is largerthan in the pressure chamber (11), it is presseddownwards together with the overflow valvespindle (16). This causes the entire pump capa-city to flow from the pressure chamber (11) intothe suction chamber (10) (circulation mode).

The pump continues to run, but only maintainsthe circulation pressure.

3. When the handgun is openedWhen the handgun is opened, the pressure inthe pressure chamber (11) and in the controlchamber (14) drops suddenly. The spring (15),together with the restricted pressure at the ent-rance to the injector (2), pushes the piston (13)upwards. The overflow valve spindle then closesoff the circulation of water between the pressurechamber (11) and the suction chamber (10) andthe pump builds up the operating pressure oncemore.

This switch-over action will not function if thereis no injector fitted or it is worn out.


3/23C22


Pressure and flow control, Servopress or manual with overflow valve

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4/23C23



1 Injector

2 Non-return valve

3 Pressure channel

4 Piston5 Rotary knob

6 Spring

7 Valve spindle

8 Valve spindle cone

9 Valve seat

10 Pressure valve

11 Cylinder head

12 Pressure chamber

13 Bypass channel

14 Suction chamber

15 Spring

16 Ball


1. Manual pressure and flow control byturning rotary knob (5)

When the handgun is opened, water is con-veyed out of the pressure chamber (12), through

the pressure valve (10), non-return valve (2) andthe injector (1), to the high-pressure outlet (17).

Turning the rotary knob (5) adjusts the initialtensioning of the spring (6). Depending on howthis spring is set, the valve opens later when theinitial tension is greater (higher operating pres-sure), or earlier when the initial tension is lower(lower operating pressure).

2. When the handgun is closed

When the handgun is closed, the pressure withinthe system reaches its maximum level. Thispressure acts upon the piston (4) via the pressu-re channel (3) and pushes the piston (4) andvalve spindle (7) downwards. The ball (16) ispushed away from the valve seat (9) and theentire pump capacity flows through the bypasschannel (13) back into the suction chamber (14).As soon as the handgun is closed the pressureis trapped between the handgun and non-returnvalve (2). This trapped pressure holds the Inst-ream valve in the by-pass mode. The pump

continues to run in low pressure operation.

3. When the handgun is opened

When the handgun is opened again, the pressu-re trapped between the handgun and the non-return valve (2) drops and the piston (4) ispushed back upwards again by the spring (6). Theball (16) closes off the valve aperture and thesystem builds up full working pressure again.


5/23C24


Pressure and flow control, Servopress with overflow valve

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6/23C25


Pressure and flow control, Servopress with overflow valve

1. When the Servopress handgun isopened

When the Servopress handgun is fully opened,water flows out of the pressure chamber (19),through the pressure holding valve (2) and injec-tor (17) then on to the high-pressure outlet (16).

The ball (4) in the overflow valve is pressed

against the valve seat (5) by the pump pressureand closes off the connecting channel (6) to thesuction chamber. The pressure gauge showsthe operating pressure within the pressure cham-ber (19). The action of the injector (17) results ina pressure level in the connecting channel (18)that is approx. 30 bar lower.

1 Threaded plug

2 Pressure holding valve

3 Spring

4 Ball5 Valve seat

6 Connecting channel to suction chamber

7 Piston

8 Threaded fitting

9 Spring

10 Rod

11 Pressure switch

12 Locking nut

13 Adjusting nut for pressure switch

14 Locking nut

15 Adjusting nut for operating pressure


17 Control pressure injector

18 Connecting channel between injectorand overflow valve

19 Pressure chamber

20 Pressure gauge connection

2. The Servopress handgun is partiallyclosed

When the handgun is partially closed, the pres-sure in the pressure chamber (19) does not

increase. Due to the decreased water flow rate,the effect of the injector action (17) is reduced,so that the pressure in the connecting channel (18)rises. The piston (7) and rod (10) are pushed tothe left slightly against the spring pressure (9).The tapered tip of the rod pushes the ball (4)away from its seat (5) slightly, so that a part of thepump flow rate flows into the suction chamber (6).

Note:

Opening or closing the Servopress handgunwhile the cleaner is operating in high-pressure mode does not result in a changeto the motor current consumption. Thecurrent consumption is only reduced whenthe cleaner is being operated in cleaningagents mode.

3. The Servopress handgun iscompletely closed

As the handgun closes, the pressure in thepressure chamber (19) rises abruptly. This peak

of pressure acts upon the piston (7) via theconnecting channel (18) and forces the rod (10)all the way to the left (approx. 4 mm). Thetapered tip of the rod (10) pushes the ball (4)completely off its seat, so that the entire pumpflow rate flows through the connecting channel(6) into the suction chamber.

As soon as the handgun is closed, the pressureholding valve (2) closes. This trapped pressureholds the valve in the by-pass mode.

When this position is reached, the pressureswitch (11) is actuated, the electrical supplyinterrupted and the motor switched off.

4. The Servopress handgun is opened

If the handgun is opened again, the pressure inthe system drops off abruptly.

The overflow valve is pushed back towards theright into its original position by the spring. Thepressure switch (11) reconnects the electricalsupply and the motor is switched on again.


7/23C26


Pressure and flow control, manual with regulating spindle

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8/23C27


Pressure and flow control, manual with regulating spindle

1 Left piston

2 Valve seat

3 Spindle cone

4 Centre piston5 Cylinder head

6 Return channel to suction side

7 Conical sleeve

8 Pressure spring

9 End limit screw

10 Regulating spindle

11 Rotary knob

Pressure and flow rate can be continuouslyadjusted with the regulating spindle.

1. The regulating spindle (10) is fully

rotated inwardsIn this position the spindle cone (3) and theconical sleeve (7) completely close off the corre-sponding apertures. The entire pump flow rate isdirected towards the handgun.

2. The regulating spindle (10) ispartially rotated outwards

In this position the spindle cone (3) has opened. Asa result the volume of water delivered by the centrepiston (4) flows back to the suction side through the

return channel (6), the pressure level and waterflow rate are reduced by approx. 3040%.

3. The regulating spindle (10) is rotatedoutwards until stopped by the endlimit screw

In this position the spindle cone (3) and theconical sleeve (7) have opened completely. Thevolume of water delivered by the centre piston (4)and the left piston (1) flows back to the suctionside through the return channel (6), the pressurelevel and water flow rate are reduced by approx.6070 %. Steam can only be generated whenthis position has been selected.

Note:The bore in the valve seat (2) varies inaccordance with the delivery capacity of theparticular unit (see Spare Parts List).


9/23C28



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10/23C29



1 Rotary knob

2 Pressure spring

3 Piston

4 Valve seat

5 Return channel

6 Pressure switch

(in circuit diagram B7)

7 Water inlet

8 Suction chamber

1. Manual pressure and flow control byturning rotary knob

If the rotary knob (1) is turned counter-clockwise, the

initial tension in the pressure spring is reduced (2).

This causes the piston (3) to lift off the valveseat (4), even at a lower pressure level and apart of the pump flow rate is directed through thereturn channel (5) into the suction chamber (8).

The pump continues to run but at a reducedpressure level. The pressure level and watervolume at the high-pressure nozzle decreaseaccording to the setting.

2. Pressure and flow control withServopress handgun

If the Servopress handgun is partially closed, thepressure within the system rises. The piston (3) israised off the valve seat (4), so that a part of thepump flow rate flows through the return channel(5) to the suction chamber (8).

The pump continues to run at high pressure. Thepressure level and water volume at the high-pressure nozzle decrease according to the set-ting.

3. The Servopress handgun is closed

If the Servopress handgun is completely closed,the piston (3) opens fully and the entire pumpflow rate flows through the return channel (5) tothe suction chamber. The dynamic pressure thatbuilds up at the entrance to the return channelactuates the pressure switch (6), which thenswitches the unit off.

Note:

The bore in the return channel (5) can vary

according to the delivery flow rate of theparticular unit (see Spare Parts List).


11/23C30


Pressure switch, two pressure switches with overflow valve

1 Rotary knob

2 Pressure spring3 Piston

4 Valve seat

5 Return channel

6 Pressure switch

7 Water inlet

8 Suction chamber

9 Suction valve

10 Pump piston

11 Pressure switch12 Non-return valve

13 Pulsation damper

14 Pressure valve

15 High-pressure connection

16 Pressure gauge connection

In this system the pump is switched on and off bytwo separate pressure switches.

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12/23C31


Pressure switch, two pressure switches with overflow valve (Schematic)

1 High-pressure outlet (no pressure)

2 Pulsation damper

3 Pressure gauge (no pressure)

4 Non-return valve (closed)

5 Rotary knob

6 Overflow valve (closed)

7 Restriction bore

8 Pressure switch (closed)

9 Water inlet

10 Motor switch contacts (open)

11 Pump (not running)


1. The unit is switched off

If the unit is switched off and the handgun hasbeen opened, there is no pressure in the systemand no electric current flows. Both pressureswitches (8) and (12) as well as the overflowvalve (6) and non-return valve (4) are closed.The motor switch contacts (10) are open.

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13/23C32



1 High-pressure outlet (operating pressure)

2 Pulsation damper

3 Pressure gauge (operating pressure)

4 Non-return valve (open)

5 Rotary knob

6 Overflow valve (closed)

7 Restriction bore


9 Water inlet

10 Motor switch contacts (closed)

11 Pump (running)

12 Pressure switch (open)

2. The unit is switched on and thehandgun opened

After the unit has been switched on and thehandgun opened, the motor contactor respondsand its contacts (10) close. The motor thenstarts up and the pump builds up the operatingpressure.

The non-return valve (4) and pressure switch (12)open, but the overflow valve (6) and pressureswitch (8) remain closed.

Because pressure switch (8) is closed, the con-tacts on the motor contactor (10) also remainclosed.

24 Volt

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14/23C33



1 High-pressure outlet (cut-out pressure)

2 Pulsation damper

3 Pressure gauge (cut-out pressure)


5 Rotary knob

6 Overflow valve (open)7 Restriction bore


9 Water inlet

10 Motor switch contacts (open)

11 Pump (not running)


3. The handgun is closed

As the handgun is closed, excess pressure isgenerated within the system for a short interval.This causes the overflow valve (6) to open, theentire pump flow rate flows through the restric-tion bore (7) into the pump suction chamber.

A dynamic pressure builds up at the entrance to

the restriction bore (7). When it reaches approx.10 bar, it opens the pressure switch (8), thisinterrupts the electrical circuit. The contacts (10)in the motor contactor open and the motor isswitched off.

As soon as the overflow valve (6) opens, the non-return valve (4) closes, the dynamic pressure isretained in between the handgun and the non-return valve (4). The pressure switch (12) is heldopen by the retained dynamic pressure.

As soon as the motor has ceased to rotate, the

overflow valve (6) and the pressure switch (8)close. The contacts (10) on the motor contactorremain open however, as there still is no flow ofelectric current due to pressure switch (12)being open.

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15/23C34



1 High-pressure outlet (no pressure)

2 Pulsation damper

3 Pressure gauge (no pressure)


5 Rotary knob

6 Overflow valve (closed)7 Restriction bore


9 Water inlet

10 Motor switch contacts (closed)

11 Pump (starts up)


4. The handgun is opened again whilethe unit is switched on

As soon as the handgun is opened, the pressuredissipates that was retained between the non-return valve (4) and the handgun. The pressureswitch (12) closes.

The electric circuit is completed again, the motorcontactor responds, its contacts (10) close, themotor starts up and the pump builds up theoperating pressure again.

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16/23C35



17/23C36


One pressure switch with overflow valve

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18/23C37


One pressure switch with overflow valve

1 Injector

2 Pressure chamber

3 Detergent non-return valve

4 Connection for detergent supply5 Control chamber

6 Detergent metering spindle

7 Rotary knob

8 Pin

9 Pressure switch

10 Pressure relief valve

11 Connecting channel

12 Suction valve

13 Pressure valve

14 Water connection with strainer

15 Pressure spring

16 Overflow piston

17 Non-return valve


1. The handgun has been opened

With the handgun open and the pump running,the injector (1) causes the pressure in the controlchamber (5) to be approx. 10 bar lower than in

the pressure chamber (2). The overflow piston isin the upper position, where it actuates thecontact in the pressure switch (9) via the pin (8).The electrical circuit is completed and the motorruns.


If the handgun is closed, water no longer flowsthrough the injector (1). As a result the pressurein both the pressure chamber (2) and the controlchamber (5) is the same. Due to the largersurface of the overflow piston (16) in the control

chamber (5) than in the pressure chamber (2), theoverflow piston is pressed downwards and opensthe connection between the pressure chamberand the suction chamber. At the same time thecontact on the pressure switch (9) is opened bymeans of the pin (8), the electrical circuit isinterrupted and the motor is switched off.

When the handgun is closed, the pressure in thepressure chamber rises abruptly for an instant.The non-return valve (17) closes and before themotor comes to a halt, the peak of pressure isdissipated through the connecting channel (11) by

the pressure relief valve (10).

The cut-out pressure remains in the system foras long as the handgun is closed.

3. The handgun is opened

If the handgun is opened again, the pressure inthe high-pressure hose and in the control cham-ber (5) drops off. The pressure spring (15)underneath the overflow piston (16) pushes thepiston upwards and closes the contact in thepressure switch (9) by means of the pin (8). The

electrical circuit is completed and the motorstarts without any back pressure.


19/23C38


One pressure switch without overflow valve

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20/23C39


One pressure switch without overflow valve

1 Electrical connecting cable

2 Cover

3 Adjusting cam

4 Microswitch5 Pin

6 Spring

7 Upper piston

8 Range of movement for rod

9 Outer spring

10 Inner spring

11 Rod

12 Disc

13 Lower piston

14 From the pump

15 Strainer

16 To the low-water protection

1. The handgun has been opened

With the handgun open and the pump running,the lower piston (13) is pushed upwards by afew millimetres against the tension of the inner

spring (10). Due to the range of movement (8)of the rod (11) in the upper piston (7), this is notsufficient to actuate the microswitch (4).


If the handgun is closed, the pressure risesabruptly. The lower piston (13) is pushed up-wards until it touches the disc (12). The rod (11)is then pushed further upwards slightly (approx.0.71.7 mm), against the tension of the inner (10)and outer springs (9), until the pin (5) actuatesthe microswitch (4), which in turn switches the

unit off.

The pin (5) and spring (6) serve solely as a safetybuffer. If the piston (7) is pushed too far upwards,the pin (5) and spring (6) prevent any damageoccurring to the microswitch (4).

The cut-out pressure remains in the system foras long as the handgun is closed.

3. The handgun is opened

If the handgun is opened, the pressure within the

system drops and the rod (11) is pushed down-wards again by the inner (10) and outer (9)springs.

Due to its range of movement (8) the rod (11) inthe upper piston (7) is subject to a short delay(approx. 12 sec) before it too is drawn down-wards, so that the microswitch (4) is switched onagain. During this interval however, the pressu-re in the system can be almost entirely dissipa-ted, so that the motor can start up without anyback pressure.

The adjusting cam (3) is used to set up themicroswitch (4) so that the unit is switched offwhen the pressure rises to approx. 10 bar abovethe working pressure.

The pressure switch is a safety device. It hastherefore been sealed in the factory.


21/23C40


Safety valve and low-water protection

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Safety valve and low-water protection

1 Inlet from the pump

2 Strainer

3 Valve seat

4 Seal5 Piston

6 Housing

7 Adjusting screw

8 Pressure spring

9 Outlet to float tank

10 Reed switch

11 Threaded plug

12 Pressure spring

13 Clamping screw

14 Magnetic piston

15 Outlet to handgun

Safety valve

The safety valve protects the pump from beco-ming damaged should the pressure switch oroverflow valve malfunction by directing the enti-

re pump flow rate into the float tank.When the handgun has been opened, the safetyvalve is closed and the entire pump flow rateflows out to the handgun (15) at operating pres-sure.

If the pressure within the high-pressure systemrises to approx. 20 bar above the operatingpressure, the piston (5) is raised off the valveseat (3) and the entire pump flow rate flows intothe float tank (9). The pressure required to openthe safety valve is set up by means of theadjusting screw (7).

The safety valve is an important safety device,therefore the adjusting screw (7) has been sea-led in the factory.

Low-water protection

The low-water protection prevents the burnerfrom igniting if there is no or insufficient flow ofwater.

When the handgun has been opened and thereis an adequate flow of water, the magnetic piston(14) is pressed against the pressure spring (12).

The magnetic piston (14) causes the contact onthe reed switch (10) to close.

The strainer (2) prevents dirt from entering intothe low-water protection area.

The low-water protection is a safety device andtherefore the threaded plug (11) and the clam-ping screw (13) have been sealed in the factory.


23/23


Installation information for O-ring/support ring

1 Pressure flow direction

2 O-ring

3 Support ring

4 Piston or spindle

O-rings are frequently used whenever a seal isrequired between two areas with different pres-sure levels. Above a certain level of pressure theO-rings are made more stable by the inclusion ofsupport rings to prevent them from becomingdeformed.

It is important that they are mounted facing theright direction. The side of the support ring withthe groove must always face the O-ring.

The following rule applies to their installation:

Pressure flow direction --> O-ring --> support ring

Always use a mounting mandrel and siliconegrease for installation in order that no damage iscaused to the support ring during the assemblyprocess.

Two support rings are used if the pressure flowdirection alternates.

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Service Basic Hd-c2

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