Heat pumps · Error codes · Vaillant
531Vaillant · aroTHERM
531 on a Vaillant aroTHERM: Pump prerun correct in cooling mode
Short answer
On a Vaillant heat pump, 531 means: Pump prerun correct in cooling mode. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Pump prerun correct in cooling mode.
Part involved: Heat pump control (status/Live Monitor).
When it shows: Pump prerun correct in cooling mode.
Likely causes:
- Operating status reported by the heat pump control (not a fault in itself).
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: yes - status changes automatically with operating state.
Manual reset: not applicable.
What you can check
- Operating status only - no action needed. If heating or hot water is not being delivered for a long period, note the status code and tell your installer.
What the engineer will check
- None required unless heating/hot water is not delivered; then review status history, settings and application limits.
Who to ask for: Vaillant-trained heat pump installer/engineer (MCS-certified installer).
Certification: MCS installer certification; Vaillant product training recommended.
Sources
- Installation instructions aroTHERM VWL 55/3 A 230 V, VWL 85/3 A 230 V (GB) ↗ · 0020217827_03 · page VWL ../3 A 0020217827_03 p.29; VWL ../2 A 0020147164_09 Appendix D (status codes) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026