Heat pumps · Error codes · Cool Energy
P1Cool Energy · EcoStore all-in-one exhaust-air DHW heat pump
P1 on a Cool Energy EcoStore all-in-one exhaust-air DHW heat pump: System high pressure protection (>=2.76 MPa active, <=2.07 MPa inactive)
Short answer
On a Cool Energy heat pump, P1 means: System high pressure protection (>=2.76 MPa active, <=2.07 MPa inactive). The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: System high pressure protection (>=2.76 MPa active, <=2.07 MPa inactive).
Likely causes:
- System blocked.
- Air or water or excess refrigerant in system (after repair).
- Water temperature sensor malfunction.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
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 EcoStore Heat Pump Water Heater - manual Rev1 ↗ · Rev1 · page 24-26 (printed) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026