P12 on a Grant Aerona 290: DC fan 2 failure
Short answer
On a Grant heat pump, P12 means: DC fan 2 failure. 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: DC fan 2 failure.
Part involved: DC fan motor / refrigerant PCB (drive PCB on 15.5 kW).
Likely causes:
- The fan is faulty or stuck.
- The refrigerant PCB is faulty (or drive PCB on 15.5 kW models).
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.
Resetting itself: Not stated in DOC 0204.
Manual reset: DOC 0204 s11.1: once the fault is resolved, reset by turning the unit OFF and back ON; s11.5: power cycle can be done from the Aerona Smart Controller touchscreen instead of the external isolator (installer procedure).
What you can check
- Note the exact code shown on the controller display and tell your installer or Grant-trained engineer.
- Check the outdoor unit air inlet and fan outlet are not blocked by leaves, snow, ice or stored objects.
What the engineer will check
- Check whether the fan is stuck or obstructed; remove obstructions or replace fan.
- Check refrigerant PCB (or drive PCB on 15.5 kW models); replace if faulty.
Who to ask for: Grant-trained heat pump engineer.
What you might notice
What owners and engineers report
1 owner and engineer report mentions this.
- Outdoor fan not spinning on the Aerona 290: 1 report
Sources
- Grant Aerona 290 Air to Water Air Source Heat Pump Range - Installation & Operating Instructions (UK DOC 0204) ↗ · Rev 1.9 · page 54 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026