Heat pumps · Error codes · Hitachi
F03Hitachi · Yutaki M (RHUE, 1st generation)
F03 on a Hitachi Yutaki M: No HC1 supply water temperature sensor, short circuit or out of range (mixing circuit only)
Short answer
On a Hitachi heat pump, F03 means: No HC1 supply water temperature sensor, short circuit or out of range (mixing circuit only). 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: No HC1 supply water temperature sensor, short circuit or out of range (mixing circuit only).
Part involved: ATW-CPA-02 advanced system controller.
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 - when condition clears.
What you can check
- Read and note the alarm code and any retry code (e.g. P70) shown on the unit controller.
- Check the heat pump supply breaker/isolator at the consumer unit is ON.
- Restart once via the unit controller (or switch off/on at the isolator) - the manual states the unit must be stopped to release most alarms; if the code returns, call an engineer.
What the engineer will check
- Check sensor operation and wiring.
Who to ask for: Heat pump service engineer.
What you might notice
Sources
- YUTAKI M Series RHUE-3AVHN1 / RHUE-(3-6)A(V)HN-HM Technical Catalogue ↗ · TCGB0090 rev.0 - 12/2013 · page p.140-141 (PDF p.148-149) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026