Heat pumps · Error codes · Fujitsu
368Fujitsu · WATERSTAGE split (Comfort, High Power, Super High Power)
368 on a Fujitsu WATERSTAGE split: Relay test active
Short answer
On a Fujitsu heat pump, 368 means: Relay test active. The manual does not say whether the heat pump stops.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Relay test active.
Part involved: hydraulic unit controller.
Likely causes:
- Displayed as 'Error 368' when relay test (line 7700) is active.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The manual does not say whether the heat pump stops.
Resetting itself: no.
Manual reset: no.
What you can check
- Note the error number shown after pressing the Info (i) key on the Waterstage user interface. Check the heat pump breakers/isolators are on. The user manual RESET key/'Reset HP' is for installers ('do not use during normal operation') - contact your installer if the fault remains.
What the engineer will check
- Set relay test back to 'No test' after commissioning tests.
Who to ask for: Heat pump / refrigeration engineer (manufacturer-trained).
Certification: F-gas certification for refrigerant-circuit work; electrical competence (Part P/18th Edition) for PCB/wiring.
What you might notice
Sources
- AIR TO WATER Comfort series DESIGN & TECHNICAL MANUAL Split type ↗ · DA_CF002EF_07 · page DTM p.113 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026