S.288 on a Vaillant aroTHERM plus: Fan 2: Wind Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong outside wind
Short answer
On a Vaillant heat pump, S.288 means: Fan 2: Wind Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong outside wind. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Fan 2: Wind Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong outside wind.
Part involved: Heat pump control (status/Live Monitor).
When it shows: Fan 2: Wind Before starting, the fan rotates at a speed of 50 rpm or higher. This may be caused by a strong outside wind.
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
- Status only: strong wind is turning the fan before start-up. Check the outdoor unit's air inlet and outlet are not blocked by leaves, debris, snow or ice build-up and clear any loose debris from around it (do not open the casing, poke the fins or use tools).
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.
What you might notice
What owners and engineers report
2 owner and engineer reports mention this.
- Intermittent fault on the aroTHERM plus (VWL ../6 A): 2 reports
Sources
- Heat pump control interface module (VWZ AI) operating and installation instructions ↗ · 0020291573_01 · page VWZ AI appliance interface 0020291573_01 p.33; uniTOWER VIH QW 190/6 E 0020291525_05 p.58; VWZ MEH 97/6 hydraulic station 0020291544_03 p.50; aroTHERM split hydraulic station VWL ../5 IS 0020257319_05 p.55 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026