Heat pumps · Error codes · Cool Energy
Er28Cool Energy · Inverter range CE-iH (R410A, c.2020)
Er28 on a Cool Energy Inverter range CE-iH: High Pressure Fault
Short answer
On a Cool Energy heat pump, Er28 means: High Pressure Fault. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: High Pressure Fault.
When it shows: p.21: discharge temperature >=115C for 30 s.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: p.21: resumes automatically after 3 minutes (as discharge-temperature protection).
What you can check
- Read and note the code shown on the controller display, then contact your installer or service engineer.
- Check the heating system pressure gauge reading against the value in your handover documents (manufacturer commissioning values: typically 1-2 bar) and that the filling loop is closed.
- Check the outdoor unit/air grilles are not blocked by debris, leaves or snow.
What the engineer will check
- Check water flow first (high pressure is often caused by low flow).
- Check refrigerant pressures/temperatures with gauges (F-gas qualified).
- Check for refrigerant leak or blockage, EEV operation and pressure switches/transducers.
Who to ask for: refrigeration / F-gas heat pump engineer.
Certification: F-gas certification (Category I) for refrigerant circuit work.
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