Heat Pump Fault Codes

Low water pressure in the system

Possible Cause:

• The water pressure in your system is below the normal range of 1 to 1.5 bar

• Loose, disconnected, or faulty wiring for the pressure sensor

• Water pressure sensor faulty

• Expansion vessel faulty

How to fix it:

If your system water pressure is showing less than 1 bar:

This can be solved without an engineer if you are competent to do so. The following guidance and resources are used at your own risk, Glow-worm accepts no liability as a result.

• Locate your filling loop (unsure? Download your user manual here)

• Slowly increase the water pressure to be between 1 to 1.5 bars

If you need further support, please contact our homeowner technical support line on0330 100 3540 option 4.

If your system water pressure is showing more than 1 bar:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3143 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Coding resistor fault

Possible Cause:

• Coding resistor damaged or not set

• Damage to coding resistor wiring harness

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glowworm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

De-icing was unsuccessful

Possible Cause:

• Electric back-up heater is not sufficient or is not available at all

• Insufficient heat energy in the house installation

• Ice formation on the evaporator

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor inlet temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the compressor inlet temperature sensor

• Compressor inlet temperature sensor defective

How to fix it:

This is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor outlet temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the compressor outlet temperature sensor

• Compressor outlet temperature sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Webto arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Building circuit return temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the building circuit return temperature sensor

• Building circuit return temperature sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Building circuit flow temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the building circuit flow temperature sensor

• Building circuit flow temperature sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Evaporator inlet temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the evaporator inlet temperature sensor

• Evaporator inlet temperature sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Refrigerant high pressure sensor fault

Possible Cause:

• Fault in the electrical connection for the refrigerant high pressure sensor

• Refrigerant high pressure sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Electric expansion valve fault

Possible Cause:

• Fault in the electrical connection for the electric expansion valve

• Electric expansion valve defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Condenser outlet temperature sensor fault

Possible Cause:

• Fault in the electrical connection for the condenser outlet temperature sensor

• Condenser outlet temperature sensor defective

How to fix it:

This is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Low refrigerant pressure sensor fault

Possible Cause:

• Refrigerant levels too low

• Incondensable particles in the refrigerant circuit

• Electronic expansion valve fault

• Fault in the electrical connection of the Low-pressure sensor

• Low-pressure sensor fault

How to fix it:

This is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Fan unit blocked (fan 1 in the case of a twin fan heat pump)

Possible Cause:

• Damage or blockage to fan blade

• Faulty fan motor

• Fault in the electrical connection to the fan motor

• HMU fault

• Installer board fault

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor outlet temperature too low

Possible Cause:

• Fault in the electrical connection of the compressor outlet temperature sensor

• Compressor outlet temperature sensor fault

• Fault in the electrical connection of the high pressure sensor

• High pressure sensor fault

• Electronic expansion valve fault

• 4 way valve fault

• Refrigerant volume too high

How to fix it:

This is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Refrigerant high pressure switch open

Possible Cause:

• Fault in the electrical connection of the high pressure switch

• High pressure switch fault

• Electronic expansion valve fault

• 4 way valve fault

• Refrigerant flow too low

• Condenser blocked or restricted (see F.532)

• Building circuit flow rate too high or too low (see F.532)

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is working with the heating system with regards to flow rates, air or blocked filter causing poor thermal transfer to the heating system. This is usually indictive if the heat pump operating for a short period following a reset to clear the fault code.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above or if the fault code reappears immediately after a reset, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor outlet temperature too high

Possible Cause:

• Fault in the electrical connection of the compressor inlet or outlet temperature sensor

• Compressor inlet or outlet temperature sensor fault

• Electronic expansion valve fault

• Refrigerant volume too low

• Building circuit flow rate too low

• Blocked or restricted filter or Y strainer

• Air in the building circuit

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is working with the heating system with regards to flow rates, air or blocked filter causing poor thermal transfer to the heating system.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Evaporation temperature too low

Possible Cause:

• Lack of servicing, dirt or debris blocking external air heat exchanger

• Compressor inlet temperature sensor

• Electronic expansion valve fault

• Refrigerant volume too low

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is drawing air through the outdoor unit with regards to dirt or debris blocking the external air heat exchanger.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Condensation temperature too low

Possible Cause:

• Electronic expansion valve fault

• Fault in the electrical connection of the compressor inlet temperature sensor

• Compressor inlet temperature sensor fault

• Low refrigerant volume

• Fault in the electrical connection of the high pressure sensor

• High pressure sensor fault

• Building circuit pressure too low

How to fix it:

If your system water pressure is showing less than 1 bar:

This can be solved without an engineer if you are competent to do so. The following guidance and resources are used at your own risk, Glow-worm accepts no liability as a result.

Locate your filling loop (unsure? Download your user manual here)

Slowly increase the water pressure to be between 1 to 1.5 Bar

If you need further support, please contact our homeowner technical support line on 0330 100 3540 option 4.

If your system water pressure is showing more than 1 bar:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3143 or visit myGlow-worm web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Evaporation temperature too high

Possible Cause:

• Poor air flow through the evaporator

• Poor heat transfer into the heating circuit (see F.733)

• Electronic expansion valve fault

• Fault in the electrical connection of the evaporator temperature sensor

• Evaporator temperature sensor fault

• High refrigerant volume

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is drawing air through the outdoor unit with regards to dirt or debris blocking the external air heat exchanger or poor heat transfer away from the heat pump into the heating circuit.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glowworm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Condensation temperature too high

Possible Cause:

• Building circuit flow rate too high or too low, lack of heat transfer into the building circuit

• Air in the building circuit

• Blocked or restricted filter or Y strainer

• Circulation pump

• Electronic expansion valve fault

• Refrigerant volume too high

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is working with the heating system with regards to flow rates, air or blocked filter causing poor thermal transfer to the heating system.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Low refrigerant volume

Possible Cause:

• Low refrigerant volume

• Fault in the electrical connection of the compressor inlet or outlet temperature sensor

• Compressor inlet or outlet temperature sensor fault

• Fault in the electrical connection of the refrigerant low- or high-pressure sensor

• Refrigerant low- or high-pressure sensor fault

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Frequency convertor (invertor board) fault

Possible Cause:

• Incoming main voltage is not within permissible tolerances

• Electrical phases incorrect

• Reverse polarity

• Poor earthing

• Unstable power supply

• Fault in the wiring harness or connector to the invertor PCB

• Fault in the wiring harness or connector to the compressor

• Fault in the invertor PCB

How to fix it:

This is a case for a Glowworm installer in the first instance, as it can relate to the electrical supply to the heat pump.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Webto arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Frequency convertor (invertor board) not recognised/connection fault

Possible Cause:

• Fault in the wiring harness or connector to the invertor PCB

• Fault in the wiring harness or connector to the compressor

• Fault in the invertor PCB

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Incorrect position of the 4-port valve

Possible Cause:

• 4-ort valve stuck in the incorrect position

• 4-port valve coil incorrectly fitted or faulty

• Incorrectly positioned flow or return temperature sensor

• Pipework incorrectly connected (flow and return pipework crossed)

• Fault in the electrical connection of the flow or return temperature sensor

• Fault in the electrical connection of the EEV temperature sensor

• EEV temperature sensor fault

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to the orientation of the pipework to the heat pump.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor phase error

Possible Cause:

• Supply phase error/ fault or reversed (400v versions only)

• Supply voltage too low or fluctuating

• Fault in the electrical connection to the invertor

• Invertor fault

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to the incoming power supply to the heat pump.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Fan unit 2 blocked

Possible Cause:

• Damage or blockage to fan blade

• Faulty fan motor

• Fault in the electrical connection to the fan motor

• HMU fault

• Installer board fault

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Building circuit pump fault

Possible Cause:

• Fault in the electrical connection to the building circuit pump

• Fault in the wiring harness to the building circuit pump

• Faulty building circuit pump

• Air in the building circuit

• Blocked or restricted filter or Y strainer

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to how the heat pump is working with the heating system with regards to flow rates or air in the heating system.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Frequency convertor (invertor PCB) fault – Compressor fault

Possible Cause:

• Fault in the wiring harness or connector to the compressor

• Fault in the invertor PCB

• Compressor fault

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Frequency convertor (invertor PCB) fault – Mains voltage fault

Possible Cause:

• Incoming main voltage is not within permissible tolerances

• Electrical phases incorrect (400V versions only)

• Reverse polarity

• Poor earthing

• Unstable power supply

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to the power supply to the heat pump.

To solve it please contact your heating installer or find your nearest installer here.

Glow-worm will attend to any fault code, however we reserve the right to charge a call out fee for non-product faults.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Invertor has overheated

Possible Cause:

• Blockage or restriction in air flow through the invertor

• Maximum operating ambient temperature exceeded (46°C)

• Faulty fan operation or damaged

• Invertor fault

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Building circuit pump connection fault

Possible Cause:

• Fault in the wiring harness to the building circuit pump

• Faulty building circuit pump

How to fix it:

This is a case for a Glowworm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Compressor temperature switch has triggered

Possible Cause:

• Electronic expansion valve (EEV) fault

• Fault in the electrical connection to the EEV

• Contamination in the refrigerant circuit i.e. dirt or moisture

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Webto arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Condenser inlet temperature sensor in the refrigerant circuit

Possible Cause:

• Fault in the electrical connection for the compressor inlet temperature sensor

• Compressor inlet temperature sensor defective

How to fix it:

This is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Invertor phase failure

Possible Cause:

• Incoming main voltage is not within permissible tolerances

• Electrical phases incorrect (400V versions only)

• Reverse polarity

• Poor earthing

• Unstable power supply

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to the power supply to the heat pump.

To solve it please contact your heating installer or find your nearest installer here.

Glow-worm will attend to any fault code; however, we reserve the right to charge a call out fee for non-product faults.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Communication between indoor and outdoor unit not possible due to incorrect communication protocol

Possible Cause:

• Incorrect appliance interface

• Fault in the wiring or connection between the heat pump and heat pump interface

• Incorrect connection of Ebus components to communication connection between indoor and outdoor units

How to fix it:

This is a case for a Glow-worm installer in the first instance, as it can relate to communication cable connecting the heat pump to the indoor interface and or Ebus controls system.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.

Communication fault between the heat pump to all Ebus controllers/wiring centres

Possible Cause:

• Incoming main voltage is not within permissible tolerances to heat pump

• Fault in the wiring or connection between the heat pump interface and VR71

• Fault in the wiring or connection between the VR71 and any wireless receivers

• Reverse polarity in the Ebus connection at all terminals

• Insufficient cable diameter, min requirements 0.75mm twin core

• Induced current from mains cables, min 120mm separation distance

• Incorrect Ebus cable type, twisted multicore cables not permissible

• Shielding cable not permissible unless suitably earthed

• Fault in the wiring or connection between the HMU and installer PCB

• Faulty HMU

How to fix it:

This is a case for a Glowworm installer in the first instance, as it can relate to Ebus communication cable connecting the heat pump to the controls system.

To solve it please contact your heating installer or find your nearest installer here.

With exception to the above, this is a case for a Glow-worm engineer. Don’t try to solve it yourself as opening the heat pump casing can be dangerous.

To solve it please contact our customer service team on 0330 100 3540 or visit myGlow-worm Web to arrange a visit from a Glow-worm engineer.

Often resetting your heat pump can resolve a fault or temporarily get your heat pump working again. Follow this link to find your user manual which will help you to reset your heat pump.