Heat pumps · Error codes · Warmflow
F101Warmflow · Zeno R290 air source heat pump AS01-R290/AS02-R290/AS03-R290
F101 on a Warmflow Zeno R290 air source heat pump AS01-R290/AS02-R290/AS03-R290: Fan Driver Power input Phase Error
Short answer
On a Warmflow heat pump, F101 means: Fan Driver Power input Phase Error. 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: Fan Driver Power input Phase Error.
Part involved: DC fan motor / fan driver board.
Likely causes:
- The fan has lost phase.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
- Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).
- Check the outdoor unit grille/coil is not blocked by leaves, debris or snow (do not open the casing).
What the engineer will check
- Check the connection between the fan module and fan motor.
- Replace the fan board.
Who to ask for: heat pump electrical.
Certification: Electrical competence for work inside the outdoor unit.
What you might notice
Sources
- Warmflow High Efficiency Variable Speed Air Source Heat Pumps A-Series AS01-R290 / AS02-R290 / AS03-R290 - User, Installation & Service Instructions, Guarantee (9009049 Rev D) ↗ · 9009049 Rev D · page 60 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026