| Code | Description | Symptom | Possible cause | Remedy | Model |
|---|---|---|---|---|---|
| #* | Communication failure | No control on faulty unit | Bad data-cable connection or damaged cable | Check data cable(s) and plugs. Repair or replace damaged cable. | SmartElec2 |
| # E1 | Air sensor temperature too high / air sensor failure | Fan operating, no heat | High ambient air temperature, impeller turning the wrong way, motor failure, air-sensor cable disconnected, air sensor broken | Check ventilation, impeller rotation, motor, cable; replace the air sensor if needed. | SmartElec2 |
| # E3 | Heatsink too hot | Fan operating, no heat | High ambient air or faulty base unit | Replace the SmartElec base unit. | SmartElec2 |
| # E4 | Heatsink sensor failure | Fan operating, no heat | Heatsink sensor wiring disconnected or faulty | Check the wiring. | SmartElec2 |
| # E5 | External temperature | Unit runs, but no external temperature control | External temperature sensor faulty | Replace the sensor. | SmartElec2 |
| # E6 | Overheat thermostat open circuit | Fan operating, no heat | Overheat thermostat open circuit | Reset or replace the overheat thermostat. | SmartElec2 |
Gas work stays with a Gas Safe registered engineer. These steps are guidance from the manufacturer sequence, not a substitute for the handbook.