Gas Safe: Gas work, flue work, and PCB replacement on a gas boiler must be carried out by a Gas Safe registered engineer. Homeowners can check obvious items such as heating pressure, condensate overflow, and whether a control is unplugged — then call an engineer.
Always confirm the part number against the boiler GC number and the installation manual before ordering.
Overview
F.32 means the PCB is not seeing a valid fan speed signal (Hall sensor). The fan is unplugged, jammed, failed, or the PCB is not driving / reading it.
Vaillant meaning: Fan fault
Possible causes
- Fan plug not fully home
- PCB multiplug not fully home
- Broken fan loom
- Fan seized or obstructed (debris, condensate, ice)
- Hall sensor failed (fan assembly)
- PCB output / input failed
Possible solutions
- Isolate, remove the case, and check the fan electrical plug and the PCB plug.
- Turn the fan by hand (cold). It should spin freely. Clear debris from the volute and flue.
- With an engineer’s meter, confirm the PCB is supplying the fan and that a speed signal returns. No supply → PCB or loom; supply but no signal → fan.
- Replace the fan as a matched assembly. Do not oil a failed Hall sensor fan.
Possible parts needed
- Fan assembly for the exact GC number (includes Hall sensor)
- Fan wiring harness
- PCB