Heat pumps · Error codes · Cool Energy
Er24Cool Energy
Er24 on a Cool Energy heat pump: Self check fault
Short answer
On a Cool Energy heat pump, Er24 means: Self check fault. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the Inverter range CE-iH (R410A, c.2020)
The manual says: Self check fault.
On the Pro Range CE-H (fixed-speed)
The manual says: Constant temperature sensor fault.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
On the Inverter range CE-iH (R410A, c.2020)
- 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).
On the Pro Range CE-H (fixed-speed)
- Read and note the code shown on the controller display, then contact your installer or service engineer.
What the engineer will check
On the Inverter range CE-iH (R410A, c.2020)
- Power-cycle / re-initialise parameters as instructed by the manufacturer.
- Check controller firmware/parameters.
- Replace controller/PCB if the fault persists.
Who to ask for: heat pump controls.
Certification: Electrical competence.
On the Pro Range CE-H (fixed-speed)
- Check the named sensor/probe connection at the PCB (loose/oxidised plug).
- Measure sensor resistance against the manufacturer table and replace if faulty.
- Check controller/PCB if sensor is good.
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
- Cool Energy Pro Monoblock Series Heat Pump Water Heaters - Installation and Users Guide Version 5 ↗ · Version 5 · page 25 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026