H06.24 on a Baxi HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP: Refr high pressure The refrigerant high pressure protection is activated
Short answer
On a Baxi heat pump, H06.24 means: Refr high pressure The refrigerant high pressure protection is activated. 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: Refr high pressure The refrigerant high pressure protection is activated.
Part involved: refrigerant pressure / temperature.
Likely causes:
- Heating/DHW mode: The water flow rate is low, the water temperature is high: if there is air in the water system, release the air. The water pressure is below 0.1 MPa: add water to the circuit until the pressure is between 0.15 and 0.2 MPa. The refrigerant level is too high. Adjust the quantity of refrigerant. The electric expansion valve is locked or the winding connector is loose. Tap the valve body and connect/disconnect the connector several times to check that the valve is working correctly. Fit the winding in the correct position. DHW mode: the water tank's heat exchanger is smaller. Cooling mode: The heat exchanger cover has not been taken off: remove the cover The heat exchanger is dirty or clogged. Clean the heat exchanger.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: yes - system restarts automatically when the cause disappears (may run in degraded/back-up mode meanwhile).
Manual reset: not required once cause removed.
What you can check
- Note the exact code shown on the controller and when it appeared.
- Check the outdoor unit is not blocked by leaves, debris, snow or covers and has clear airflow.
- The manual's user steps allow switching the system off and on once to see if the error clears; if the code returns, contact the installer.
- If the code persists or returns, contact a heat pump engineer.
What the engineer will check
- Heating/DHW mode: The water flow rate is low, the water temperature is high: if there is air in the water system, release the air. The water pressure is below 0.1 MPa: add water to the circuit until the pressure is between 0.15 and 0.2 MPa. The refrigerant level is too high. Adjust the quantity of refrigerant. The electric expansion valve is locked or the winding connector is loose. Tap the valve body and connect/disconnect the connector several times to check that the valve is working correctly. Fit the winding in the correct position. DHW mode: the water tank's heat exchanger is smaller. Cooling mode: The heat exchanger cover has not been taken off: remove the cover The heat exchanger is dirty or clogged. Clean the heat exchanger.
Who to ask for: heat pump / refrigeration engineer (F-gas).
Certification: F-gas certification (Category I) for refrigerant work; competence with flammable A3 refrigerant R290.
What you might notice
Sources
- Installation, user and service manual - Indoor unit ASHP Control ↗ · 7887625 - v04 - 22072025 · page 129 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026