P04 on a Technibel S.A.S. Technibel PHRIE / PHIE inverter monobloc air-to-water: High refrigerant pressure switch activated (41.5 bar) - units 257/307 only
Short answer
On a Technibel S.A.S. heat pump, P04 means: High refrigerant pressure switch activated (41.5 bar) - units 257/307 only. 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: High refrigerant pressure switch activated (41.5 bar) - units 257/307 only.
Likely causes:
- High pressure.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: Manual reset: fault memorised by A2 board; reset by A2 RESET button (5 s), setting system control to OFF, or switching off power (power-off recommended for E15/E16/E20/L02/L08/L09/L10/L13/F29/F31).
What you can check
- Note the code/LED pattern and the model from the rating plate, then contact a heat pump/refrigeration engineer.
- Check the heat pump's breaker/isolator at the consumer unit is on.
What the engineer will check
- Check A3 control board and HP switch.
Who to ask for: refrigeration / heat pump engineer.
Certification: F-gas certification (refrigerant circuit work) and electrical competence.
What you might notice
Sources
- Technibel PHRIE / PHIE inverter monoblock air to water heat pump, medium temperature, R410A - Service Manual (Jun. 2015, 10 12 211 - GB - 06) ↗ · 10 12 211 - GB - 06 · page 98 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026