alarm-circulation-pump on a Danfoss DHP-H: The circulation pump's integrated alarm has deployed (Opti models only) - pump air-locked or jammed; shake function tries up to 5 times
Short answer
On a Danfoss heat pump, alarm-circulation-pump means: The circulation pump's integrated alarm has deployed (Opti models only) - pump air-locked or jammed; shake function tries up to 5 times. 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: The circulation pump's integrated alarm has deployed (Opti models only) - pump air-locked or jammed; shake function tries up to 5 times.
Part involved: speed-controlled heating circulation pump.
Likely causes:
- Air in circulation pump; jammed circulation pump.
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.
Manual reset: Set operating mode OFF then back to the desired mode.
What you can check
- Note the exact alarm text. The manual allows acknowledging by setting the operating mode to OFF and then back to the previous mode - do this once; if the alarm returns, leave it and call an engineer. Check the heating-system pressure gauge is in the range given in the user guide (Thermia/Danfoss: 1-1.5 bar when cold) - do not top up yourself unless you have been shown how; check radiator/underfloor valves and room thermostats are open.
What the engineer will check
- Bleed heating system; cut power and manually run pump; replace if recurring; check 0-10 V signal (troubleshooting guide p.12).
Who to ask for: heat pump engineer.
What you might notice
Sources
- Service instructions DHP-A, DHP-A Opti, DHP-AL, DHP-AL Opti, DHP-C, DHP-H, DHP-H Opti, DHP-H Opti Pro, DHP-L, DHP-L Opti, DHP-L Opti Pro (VMGFC302) ↗ · VMGFC302 (© 2010; PDF regenerated 2024-07-10 on assets.danfoss.com) · page printed p.44 (Table 22); PDF p.46 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026