Heat pumps · Error codes · Cool Energy
Er23Cool Energy
Er23 on a Cool Energy heat pump: Cooling outlet water temperature supercooling protection
Short answer
On a Cool Energy heat pump, Er23 means: Cooling outlet water temperature supercooling protection. 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 · 3 sources
What it means
On the ecoTech DC Inverter (R32 EVI)
The manual says: Cooling outlet water temperature supercooling protection.
On the Inverter range CE-iH (R410A, c.2020)
The manual says: Inlet / Outlet difference too high.
On the Pro Range CE-H (fixed-speed)
The manual says: Cooling supercool protection.
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
- 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 rate and temperature sensors.
- Check set-points and system design temperatures.
- Check refrigerant charge.
Who to ask for: heat pump engineer.
Certification: None specific.
What you might notice
Sources
- Cool Energy ecoTech Monoblock Series R32 EVI Heat Pump Water Heaters - Installation and Users Guide v2.1 (2022) ↗ · Version 2.1 · page 31 · Reviewed 23 September 2026
- 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