Fuses and reset buttons on the heat pump. Bosch EHP 6-17 LW, EHP 6-11 LW, EHP 6-11 LM

What to do if a fault occurs

Fuses and reset buttons on the heat pump

LWM model

Particle fi lter

Cleanable, with shutoff switch.

Fuse 1

Reset for motor cut-out compressor.

Fuse 2

Reset switch for the heat pump’s miniature circuit-breaker.

Fuse 3

Reset switch for the electric cassette’s miniature circuit-breaker.

Fuse 4

Reset button for the electric cassette overheat protection.

Note: The button must be pressed in fi rmly.

Sight glass

LW model

Sight glass

All alarms

An alarm can sometimes occur temporarily due to various reasons.

However, there is never a risk involved in resetting an alarm. All the alarms that can appear in the menu display are described on the following pages. The descriptions give you an idea about the nature of the alarm and what you can do to rectify it. The text often refers to different fuses and reset buttons on the heat pump. These are shown in the fi gures above.

List of all alarms:

Motor cut-out compressor

Motor cut-out HTF pump

Low pressure switch

High pressure switch

Power failure (3-phase)

3-phase incorrect (3-phase)

High return to the heat pump

Heat transfer fl uid out max

High heat transfer fl uid delta

Heat transfer fl uid in under limit and heat transfer fl uid out under limit

31

What to do if a fault occurs

Motor cut-out compressor (MB1)

Possible cause 1: Intermittent fault or overload on the power supply.

Action: 1. Press the Ackn. button.

The alarm indication goes out even if the fault has not been rectifi ed.

2. Reset the motor cut-out on the heat pump (Fuse 1).

3. Wait for the heat pump to start.

Possible cause 2: Current level (A) on the motor cut-out is set too

Action: low.

The current drawn by the compressor varies during summer/winter operations.

1. Contact your dealer.

Possible cause 3: Contactor or cut-out faulty, or loose electrical connections to the compressor.

Action: 1. Contact your dealer.

Possible cause 4: Compressor error.

Action: 1. Contact your dealer.

Motor cut-out HTF pump (MB2)

Possible cause 1: The HTF pump is blocked due to contamination.

Action: 1. Press the Ackn. button.

2. Loosen the venting screw and remove the dirt.

3. Help to start the pump with a screwdriver.

The alarm indication goes out even if the fault has not been rectifi ed.

Possible cause 2: Faulty electric motor on HTF pump.

Action: 1. Contact your dealer.

Possible cause 3: Temporar y error.

Action: 1. Contact your dealer should repeated faults occur.

The menu display shows:

Alarm (MB1)

Compr. circ. switch

040622 16:08:15

Info Ackn.

Note

The reset switch for the compressor can be found under heading Fuses and resetting buttons on the heat pump.

The menu display shows:

Alarm (MB2)

HTF c-pump switch

040622 16:08:15

Info Ackn.

Note

The alarm indication goes out when acknowledging the alarm even if the fault has not been rectifi ed.

32

Compressor temperature T6 (GT6)

Possible cause 1: The working temperature of the compressor is too high.

Action: 1. Press the Ackn. button.

2. Contact your dealer at repeated alarms.

Possible cause 2: Intermittent temperature rise due to abnormal operating conditions.

Action: 1. Press the Ackn. button.

2. Wait and see.

Low pressure switch (LP)

Possible cause 1: Air in the heat transfer system.

Action: 1. Press the Ackn. button.

2. Check the expansion tank.

3. Fill with fl uid if necessary.

4. Listen for air in the system. If air is heard constantly, contact your dealer.

Possible cause 2: The particle fi lter on the cold side is clogged.

Action: 1. Check the particle fi lter.

2. Clean the particle fi lter if necessary.

3. Press the Ackn. button.

Possible cause 3: Lack of refrigerant in the heat transfer circuit.

Action: 1. Press the Ackn. button.

2. Wait for the heat pump to start.

3. Check whether it bubbles continuously in the sight glass.

4. If it bubbles continuously, contact your dealer.

Possible cause 4: The HTF pump has stopped or is set at too low a speed.

Action: 1. Press the Ackn. button.

2. Check that the pump has not stopped or is set at the wrong speed.

Possible cause 5: Ice formation in the heat exchanger due to a lack of anti-freeze in the heat transfer circuit.

Action: 1. Contact your dealer.

Possible cause 6: Faulty expansion valve (the alarm appears in time periods of 3-4 weeks).

Action: 1. Contact your dealer.

What to do if a fault occurs

The menu display shows:

Alarm (GT6)

Compressor superheat

040622 16:08:15

Info Ackn.

The menu display shows:

Alarm (LP)

Low pressure switch

040622 16:08:15

Info Ackn.

33

What to do if a fault occurs

High pressure switch (HP)

Possible cause 1: Air in the heating system.

Action: 1. Press the Ackn. button.

2. Check whether there is air in the radiators.

3. Fill the heating system and vent if necessary.

Possible cause 2: Not enough fl ow over the heat pump.

Action: 1. Press the Ackn. button.

2. Check that the heat carrier pump has not stopped.

3. Check that all the valves are open. The thermostat valves accord. to clockeating systems should be fully open and in fl oor heating systems at least half of the coils should be fully open.

4. Possibly increase the speed of the heat carrier pump.

Possible cause 3: The particle fi lter on the hot side is clogged.

Action: 1. Press the Ackn. button.

2. Check the particle fi lter.

3. Clean the particle fi lter if necessary.

Alarm (HP)

High press. switch

040622 16:08:15

Info Ackn.

Note

Increase the speed of the heat carrier pump:

Use a screwdriver or a coin to increase the speed of the heat carrier pump.

Turn one step anti-clockwise.

Electric cassette (EK)

Possible cause 1: The electric cassette’s miniature circuit-breaker has tripped.

Action: 1. Press the Ackn. button.

2. Reset the miniature circuit breaker button on the heat pump (circuit breaker 3) by pushing up the toggle switch.

3. Contact your dealer if the miniature circuit breaker trips again.

Possible cause 2: The electric cassette’s overheat protection has tripped.

Action: 1. Press the Ackn. button.

2. Reset the overheat protector (circuit breaker 4) by pressing in the button on the electric cassette’s protective casing. The circuit breaker is reset when you hear a clicking sound.

3. Check that the particle fi lter on the hot side is clean.

Alarm (EK)

Electrical cassette

(EE) 040622 16:08:15

Info Ackn.

Note

The miniature circuit-breaker button for the electric cassette can be found under the heading Fuses and reset but- tons on the heat pump .

The most frequent cause for the overheat protection tripping is a poor fl ow over the heat pump, which can be due to air in the heat pump or that the particle fi lter is clogged.

34

What to do if a fault occurs

Power failure (3-phase)

The heat pump maintains all its settings in case of a power failure. When the power returns the heat pump automatically starts up according to the previous settings.

Possible cause: One or two phases to the heat pump are down.

Action: 1. Check that the fuses in the house’s distribution box have not blown.

2. Change the fuse if necessary. If you have miniature circuit-breakers and these have tripped you reset them by pushing up the toggle switch.

3. The heat pump automatically returns to the operating mode once the fault has been rectifi ed.

Alarm

Power failure

040622 16:08:15

Info Ackn.

3-phase incorrect (3-phase)

Possible cause 1: One or two phases to the heat pump are down.

Action: 1. Check that the fuses in the house’s distribution box have not blown.

2. Change the fuse if necessary. If you have miniature circuit-breakers and these have tripped you reset them by pushing up the toggle switch.

3. The heat pump automatically returns to the operating mode once the fault has been rectifi ed.

Possible cause 2: Phase sequence to the heat pump is incorrect.

(The alarm may only be rectifi ed by an electrician.)

Action: 1. Press the Ackn. button.

2. Switch the phase sequence on the incoming supply.

The heat pump starts automatically once the phase sequence has been switched.

Alarm

3-phase incorrect

040622 16:08:15

Info Ackn.

Note

If the power does not return on all phases at the same time during external electrical work, there is a risk that the Rego control unit gives a false alarm for a phase sequence error.

High Heat transfer fl uid delta T8/T9 (GT8/GT9)

The heat pump gives an alarm when the temperature difference between the sensors T8 (GT8) and T9 (GT9) is too high.

Possible cause 1: Not enough fl ow over the heat pump.

Action: 1. Check that the heat carrier pump has not jammed.

2. Check that all the valves are open. The thermostat valves accord. to clockeating systems should be fully open and in fl oor heating systems at least half of the coils should be fully open.

Possible cause 2: The particle fi lter on the hot side is clogged.

Action: 1. Clean the particle fi lter.

Alarm GT8/GT9

High HTF delta

040622 16:08:15

Info Ackn.

35

What to do if a fault occurs

High return to the heat pump T9 (GT9)

There is a sensor T9 (GT9) in the heat pump, which for reasons of safety, stops the compressor if the temperature of the return water from the radiators becomes too high. The limit lies at approximately 58ºC.

Possible cause 1: The temperature setting is too high.

Action: 1. Lower the temperature setting (Temp. +/-).

Possible cause 2: The valves on the radiators or fl oor heating

Action: system are closed.

1. Open all valves.

2. Press the Ackn. button.

Possible cause 3: The hot water temperature is set too high.

Action: 1. An alarm is given accord. to clockot water mode.

Contact the installer to adjust the hot water temperature.

Possible cause 4: The fl ow across the heat pump is greater than the fl ow in the heating system.

(Only applies if a bypass is fi tted.)

Action: 1. Reduce the speed of the heat carrier pump or increase the speed of the main pump in the heating system.

2. Contact your dealer.

Alarm (GT9)

High return HP

040622 16:08:15

Info Ackn.

Note

The heat pump starts automatically when the temperature drops.

Lower the speed of the heat carrier pump:

Use a screwdriver or a coin to lower the speed of the heat carrier pump. Turn one step clockwise. The lowest speed should be avoided.

Heat transfer fl uid out max T8 (GT8)

There is a sensor T8 (GT8) in the heat pump, which for reasons of safety, stops the compressor if the temperature of the water going out to the radiators becomes too high.

Possible cause 1: Not enough fl ow over the heat pump.

Action: 1. Check that the heat carrier pump has not jammed.

2. Check that all the valves are open. The thermostat valves accord. to clockeating systems should be fully open and in fl oor heating systems at least half of the coils should be fully open.

Possible cause 2: The particle fi lter on the hot side is clogged.

Action: 1. Clean the particle fi lter.

Alarm (GT8)

Heat tran. f out max

040622 16:08:15

Info Ackn.

Note

The heat pump starts automatically when the alarm is reset and the water temperature has dropped to its normal value.

36

What to do if a fault occurs

Sensor fault

All sensors connected to the heat pump can give an alarm when defective. In the example to the right it is sensor T1 (GT1), Return radiator, which has given an alarm. All sensors give alarms in the same way. Read more about the sensors under heading Read the temperatures on the heat pump.

Possible cause 1: Temporar y error.

Action: 1. Wait and see.

Possible cause 2: Short circuit or broken sensor cable.

Action: 1. If you have an ohmmeter you can disconnect the sensor and check the cable’s resistance. Compare with the sensor table in the section Technical information.

Otherwise contact your dealer.

Possible cause 3: Defective sensor or incorrect connection.

Action: 1. Contact your dealer.

Alarm (GT1)

Sensor return rad.

040622 16:08:15

Info Ackn.

Note

Switch off the power before checking the resistance of the cable.

Note

The factory settings are 0°C and -2°C respectively. If anti-freeze liquid is used these values need to be changed.

Contact your installer

HTF in under limit T10 (GT10) and HTF out under limit T11 (GT11)

Possible cause 1: Temporar y low heat transfer fl uid temperature.

Action: 1. Wait and see.

2. If the alarm returns, contact your dealer.

Possible cause 2: Too low fl ow on the cold side.

Action: 1. Check the particle fi lter.

2. Clean the fi lter if it is clogged.

Possible cause 3: The minimum heat transfer fl uid temperature has

Action: been set too low.

1. Wait and see.

2. If the alarm returns, contact your dealer.

Alarm (GT10)

Pump inlet too cold

040622 16:08:15

Info Ackn.

Alarm (GT11)

Pump outlet too cold

040622 16:08:15

Info Ackn.

In a groundwater system the cause may also be:

Possible cause 4: Clogged fi lter in the groundwater circuit.

Action: 1. Clean the fi lter.

Possible cause 5: The motor cut-out or a fuse on the pump in the groundwater system has tripped.

Action: 1. Reset the motor cut-out or fuse.

Possible cause 6: Faulty pump in the groundwater circuit.

Action: 1. Contact your dealer.

37

What to do if a fault occurs

Anode error

Possible cause 1: Temporar y error.

Action: 1. When large amounts of hot water are used (e.g. with a bath) the alarm may be given without there being a fault. Contact your dealer at repeated alarms. If the fault occurs at the weekend, you can wait to the next working day before contacting your dealer.

Possible cause 2: Faulty electric anode.

Action: 1. Contact your dealer.

Alarm

Anode error

040622 16:08:15

Return Info

38