Joule · A niche brand in the UK. 31 codes across 2 product families, each taken from the manufacturer’s manuals. Joule 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.
31 codes
| Code | Meaning | Stops? | Homeowner check? |
|---|---|---|---|
| 10 | Water Pressure low, < 0.8 bar | No | Yes |
| 11 | Replace filter | No | Yes |
| 12 | No communication with the room thermostat | Yes | Yes |
| 13 | No communication with the boiler | Yes | Yes |
| 20 | Filter reached end of lifespan | No | Yes |
| 30 | Top tank temperature sensor error | Yes | Yes |
| 31 | Bottom tank temperature sensor error | Yes | Yes |
| 32 | Back up heater water heater temperature sensor error | Yes | Yes |
| 33 | Air-In sensor error - Green Comfort Module | Yes | Yes |
| 34 | Air-Out sensor error - Green Comfort Module | Yes | Yes |
| 35 | Airflow sensor error - Green Comfort Module | Yes | Yes |
| 36 | Frost protection active - Green Comfort Module | Yes | Yes |
| 37 | Lost connection with Green Comfort Module | Yes | Yes |
| 38 | Lost communication between ComfortZone UFH wiring centre and the Green Comfort Module | Yes | Yes |
| 51 | Air-In sensor error | Varies by model | Yes |
| 52 | Air-Out sensor error | Varies by model | Yes |
| 53 | Evaporator sensor error | Varies by model | Yes |
| 54 | HP Return sensor error | Varies by model | Yes |
| 55 | HP Supply sensor error | Varies by model | Yes |
| 56 | Hot Gas sensor error | Varies by model | Yes |
| 60 | Airflow sensor error | Varies by model | Yes |
| 70 | Water pressure sensor error | Varies by model | Yes |
| 71 | Back up heater protection active | Yes | Yes |
| 80 | No temperature difference across the condenser | Partly | Yes |
| 81 | No temperature difference across the evaporator | Partly | Yes |
| 90 | Compressor locked (repeated error 80) | Yes | Yes |
| 94 | Compressor locked (repeated error 81) | Yes | Yes |
| 95 | Water pressure is critically low (< 0.3 bar) | Yes | Yes |
| AP2 | The average central heating temperature is higher than 60C | Partly | Yes |
| AP3 | The freeze protection is active | No | Yes |
| AP4 | Pause mode - the compressor must not be started yet | Partly | Yes |