Heat pumps · Error codes · Hisa Engineering Ltd
E54Hisa Engineering Ltd · Hisa hr290
E54 on a Hisa Engineering Ltd Hisa hr290: High Pressure Two Under Voltage Protection
Short answer
On a Hisa Engineering Ltd heat pump, E54 means: High Pressure Two Under Voltage Protection. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: High Pressure Two Under Voltage Protection.
Part involved: pressure switch/sensor.
Likely causes:
- Same as E06.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
What you can check
- Note the code shown on the controller and the model number on the rating label before contacting your installer.
- Check that the heat pump isolator / consumer-unit breaker is on; do not open any casing.
- A single restart via the controller (off/on) may be tried only if the manual or your installer allows it.
What the engineer will check
- Follow the manufacturer's troubleshooting steps for this code.
- Check the relevant sensor/switch wiring and connectors.
- Measure/replace the component or PCB as indicated.
Who to ask for: F-gas / refrigerant.
What you might notice
Sources
- Hisa R290 Installation & User Manual (300824) ↗ · page 38 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026