Grant · A major brand in the UK. 136 codes across 4 product families, each taken from the manufacturer’s manuals. Grant technical support ↗
Filter by product family
Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.
136 codes
| Code | Meaning | Stops? | Homeowner check? |
|---|---|---|---|
| 01 | No communication with the controller | Partly | Yes |
| 02 | No compatibility of programs | Partly | Yes |
| 03 | Panel temperature sensor error | Partly | Yes |
| 04 | DHW sensor error | Partly | Yes |
| 05 | Upper buffer temperature sensor error | Partly | Yes |
| 06 | Lower buffer temperature sensor error | Partly | Yes |
| 07 | Circuit 2 temperature sensor error | Partly | Yes |
| 08 | Circuit 3 temperature sensor error | Partly | Yes |
| 09 | Anti-freeze active | Varies by model | Yes |
| 11 | No communication with the thermostat | Varies by model | Yes |
| 12 | No communication with thermostat circuit 1 | Partly | Yes |
| 13 | No communication with thermostat circuit 2 | Partly | Yes |
| 14 | No communication with thermostat circuit 3 | Partly | Yes |
| 15 | Alarm from digital input | Partly | Yes |
| 16 | No flow detected | Yes | Yes |
| 17 | Too often no flow detected | Yes | Yes |
| 19 | No communication with heat pump module | Yes | Yes |
| 20 | Circuit 4 temperature sensor error (not used) | Varies by model | Yes |
| 21 | Circuit 5 temperature sensor error (not used) | No | Yes |
| 22 | Circuit 6 temperature sensor error (not used) | No | Yes |
| 23 | Circuit 7 temperature sensor error (not used) | No | Yes |
| 24 | No communication with thermostat circuit 4 (not used) | No | Yes |
| 25 | No communication with thermostat circuit 5 (not used) | No | Yes |
| 26 | No communication with thermostat circuit 6 (not used) | No | Yes |
| 27 | No communication with thermostat circuit 7 (not used) | No | Yes |
| 28 | No communication with thermostat circuit 7 (not used) | No | Yes |
| 740 | Remote controller communication error | Not stated | Yes |
| 750 | Slave Remote controller communication error | Not stated | Yes |
| A0 | DC voltage error | Yes | Yes |
| A1 | Discharge temperature error | Yes | Yes |
| A2 | Protective action against excess Current DC current detection | Yes | Yes |
| A3 | CT disconnection | Yes | Yes |
| A4 | Protective action against excess Current AC current detection | Yes | Yes |
| A5 | Abnormal revolution of compressor | Yes | Yes |
| A6 | Suction temperature sensor error | Yes | Yes |
| A7 | Defrost tem sensor error | Yes | Yes |
| A8 | Discharge temp. sensor error | Yes | Yes |
| BOIL IN OPn | HP return sensor open | Not stated | Yes |
| BOIL IN SHr | HP return sensor short | Not stated | Yes |
| BOIL OUT OPn | HP flow sensor open | Not stated | Yes |
| BOIL OUT SHr | HP flow sensor short | Not stated | Yes |
| C1 | Upper fan motor error | Yes | Yes |
| C2 | Outdoor temp. sensor error | Partly | Yes |
| C3 | Lower Fan motor error / Fan motor error | Yes | Yes |
| C4 | Rise of temperature (above 110°C) of Main PCB | Yes | Yes |
| C5 | Main PCB sensor error | Yes | Yes |
| C6 | Main PCB error | Yes | Yes |
| C7 | Controller PCB serial error | Yes | Yes |
| C8 | Main PCB error | Yes | Yes |
| E01 | Communication error between Smart Controller wiring centre and heat pump (error shown on touch screen) | Yes | Yes |
| E01 Err | Internal control fault | Not stated | Yes |
| E02 | Discharge temperature sensor failure (TP) | Yes | Yes |
| E03 | Coil temperature sensor failure (T3) | Yes | Yes |
| E04 | Ambient temperature sensor failure (T4) | Yes | Yes |
| E4 | Outgoing water temp. sensor error | Yes | Yes |
| E05 | Liquid pipe temperature sensor failure (T5) | Yes | Yes |
| E5 | Return water temp. sensor error | Yes | Yes |
| E06 | Return air temperature sensor failure (TH) | Yes | Yes |
| E6 | Plate heat exchanger temp. sensor error | Yes | Yes |
| E07 | Water tank temperature sensor failure (TW) | Yes | Yes |
| E08 | Outlet water temperature sensor failure (TA) | Yes | Yes |
| E8 | Remote controller communication error | Not stated | Yes |
| E09 | Outlet water temperature sensor failure (TB) | Yes | Yes |
| E10 | Communication failure between hydraulic PCB and refrigerant PCB | Yes | Yes |
| E13 | Discharge pressure sensor fault | Yes | Yes |
| E14 | Low pressure sensor LPS failure | Yes | Yes |
| E15 | DC bus voltage is too low | Yes | Yes |
| E16 | DC bus voltage is too high | Yes | Yes |
| E17 | AC current protection (input current) | Yes | Yes |
| E18 | IPM module is abnormal | Yes | Yes |
| E19 | PFC abnormal | Yes | Yes |
| E20 | Compressor failed to start | Yes | Yes |
| E21 | Compressor phase loss | Yes | Yes |
| E22 | Inverter Module reset | No | Yes |
| E23 | Compressor over-current | Yes | Yes |
| E24 | PFC module temperature is too high | Yes | Yes |
| E25 | Current detection circuit failure | Yes | Yes |
| E26 | Out of step | Yes | Yes |
| E27 | PFC module temperature sensor is abnormal | Yes | Yes |
| E28 | Communication fail | Yes | Yes |
| E29 | IPM module temperature is too high | Yes | Yes |
| E30 | IPM module temperature sensor failure | Yes | Yes |
| E31 | Reserved | Not stated | Yes |
| E32 | Reserved | No | Yes |
| E33 | Reserved | No | Yes |
| E34 | AC input voltage is abnormal | Yes | Yes |
| E35 | Drive EEPROM error | No | Yes |
| E36 | Power off reset | Yes | Yes |
| E37 | Reserved | No | Yes |
| E38 | Reserved | No | Yes |
| E57 | GAS SENSOR OFFLINE | Yes | Yes |
| E58 | GAS SENSOR | Yes | Yes |
| EE1 | High pressure - circulating pump failure or circuit air locked | Yes | Yes |
| EE2 | Low pressure | Yes | Yes |
| EE3 | Open circuit between PCB terminals 23-24 | Yes | Yes |
| EE4 | Supply L and N are reversed | Yes | Yes |
| EE8 | Communication failure | Yes | Yes |
| F5 | Main PCB communication error | Yes | Yes |
| FU | High pressure switch is operating | Yes | Yes |
| L0 | EEPROM error | Yes | Yes |
| L1 | DHW temperature sensor error | Partly | Yes |
| L2 | Outdoor temperature sensor error | Partly | Yes |
| L3 | Thermal store temperature sensor error | Partly | Yes |
| L4 | Mix water temperature sensor error | Partly | Yes |
| L5 | Humidity sensor error | Partly | Yes |
| L6 | Flow switch error | Yes | Yes |
| L7 | Mixing valve error | Partly | Yes |
| L8 | Room temp. (Master Remote controller) error | Partly | Yes |
| L9 | Room temp. (Slave Remote controller) error | Partly | Yes |
| LC | Anti Legionella Function Not completed | No | Yes |
| OUTDR OPn | Outdoor sensor open | Not stated | Yes |
| OUTDR SHr | Outdoor sensor short | Not stated | Yes |
| P01 | Water flow protection | Yes | Yes |
| P1 | Pump error | Yes | Yes |
| P02 | High pressure protection | Yes | Yes |
| P03 | Low pressure protection | Yes | Yes |
| P3 | High pressure switch error | Yes | Yes |
| P04 | Condenser temperature overheat protection | Yes | Yes |
| P05 | Discharge temperature protection | Yes | Yes |
| P08 | Middle pressure protection | Yes | Yes |
| P11 | DC fan 1 failure | Yes | Yes |
| P12 | DC fan 2 failure | Yes | Yes |
| P13 | 4-way valve fault | Yes | Yes |
| P14 | Refrigerant leakage fault | Yes | Yes |
| P21 | Abnormal operation of DC pump | Yes | Yes |
| P25 | Outlet pressure sensor failure | Yes | Yes |
| PP1 | Inlet (return) water temperature sensor failure | Yes | Yes |
| PP2 | Discharge gas sensor failure | Yes | Yes |
| PP3 | Coil temperature sensor failure | Yes | Yes |
| PP4 | Return gas sensor failure | Yes | Yes |
| PP5 | Ambient temperature sensor failure | Yes | Yes |
| PP6 | Discharge gas overheat protection | Yes | Yes |
| PP7 | Winter anti-freeze protection in operation | No | Yes |
| SUP OPn | Supply sensor open | Not stated | Yes |
| SUP SHr | Supply sensor short | Not stated | Yes |
| U1 | Compressor overheat protection relay operation | Yes | Yes |