Heat pumps · Error codes · Cool Energy
Er31Cool Energy · Pro Range CE-H (fixed-speed)
Er31 on a Cool Energy Pro Range CE-H: Water pressure switch fault (troubleshooting table 'Error code 31'; not in common code table)
Short answer
On a Cool Energy heat pump, Er31 means: Water pressure switch fault (troubleshooting table 'Error code 31'; not in common code table). 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: Water pressure switch fault (troubleshooting table 'Error code 31'; not in common code table).
Likely causes:
- Water pressure switch plug disconnected/oxidised.
- Water pressure switch cable damaged.
- Controller/PC board faulty.
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.
What the engineer will check
- Reconnect/clean water pressure switch connection.
- Replace cable.
- Replace controller/PC board.
- Check and restore system pressure via filling loop.
- Check for leaks and expansion vessel charge.
- Check water pressure sensor/switch and wiring.
Who to ask for: heating / plumbing heat pump installer.
Certification: None specific.
What you might notice
Sources
- Cool Energy Pro Monoblock Series Heat Pump Water Heaters - Installation and Users Guide Version 5 ↗ · Version 5 · page 30 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026