Heat pumps · Error codes · Fujitsu
516Fujitsu · WATERSTAGE split (Comfort, High Power, Super High Power)
516 on a Fujitsu WATERSTAGE split: Heat pump missing
Short answer
On a Fujitsu heat pump, 516 means: Heat pump missing. 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: Heat pump missing.
Part involved: sensor/controller: X60.
Likely causes:
- Loss of connection between controller and heat pump.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
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
- Check the wiring between X60 and the interface board.
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
- Maintenance Document - Air to Water Heat Pump Split single service and integrated DHW type (Super High Power) ↗ · 2105_EN_1 · page SHP SM p.5; SHP IM p.74 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026