Heat pumps · Error codes · Cool Energy
Er08Cool Energy · Inverter range CE-iH (R410A, c.2020)
Er08 on a Cool Energy Inverter range CE-iH: Controller and PCB communication fault
Short answer
On a Cool Energy heat pump, Er08 means: Controller and PCB communication fault. The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Controller and PCB communication fault.
When it shows: Remote controller receives no communication from PCB for 10 s (p.21).
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: Fault disappears when communication restored; unit keeps working to original settings (p.21).
What you can check
- Read and note the code shown on the controller display, then contact your installer or service engineer.
- Check the heat pump's breaker/isolator at the consumer unit is switched on (do not repeatedly reset if it trips).
What the engineer will check
- Check communication cable between controller/PCB/driver board (type, polarity, termination).
- Check power supply to the remote module.
- Replace faulty PCB/controller if wiring is sound.
Who to ask for: heat pump controls / electrical.
Certification: Electrical competence.
What you might notice
Sources
- Cool Energy Inverter Monoblock Series Heat Pump Water Heaters - Installation and Users Guide Version 5 ↗ · Version 5 · page 22 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026