F.32
Vaillant Boiler
Severity: ModerateWhat Does This Error Mean?
Vaillant F.32 means the fan speed reported back to the PCB does not match the speed the PCB commanded.
The fan either runs too slowly, too quickly, or not at all.
Cause is usually a flue restriction, a Hall-effect sensor inside the fan failing, or wiring at the fan connector loose.
Less commonly, the fan motor itself has worn out after years of service.
Affected Models
- Vaillant ecoTEC Plus
- Vaillant ecoTEC Pro
- Vaillant ecoFIT Pure
- Vaillant ecoFIT Sustain
Common Causes
- Flue blocked by leaves, nest, or ice at the termination
- Fan blade clogged with dust or condensate residue
- Hall-effect sensor in the fan failed
- Fan motor bearing worn
- Connector at the fan loose after vibration over years
- PCB fan-driver section damaged
How to Fix It
-
Check the flue termination.
Walk to where the flue exits the wall or roof.
Look for nests, leaves, or icing in cold weather.
Clear gently with a soft brush.
This single step solves a meaningful fraction of F.32 reports. -
Reset the boiler.
If the obstruction was external, press the reset button.
The boiler attempts a fresh ignition.
If F.32 returns, the issue is internal. -
Engineer step: power off and inspect fan.
A Gas Safe engineer powers down the boiler at the spur, removes the front cover, and accesses the fan.
Visible dust or condensate-residue on the blades reduces speed and causes F.32. -
Engineer step: check fan harness.
Fan harness pins corrode after long-term exposure to combustion chamber humidity.
Disconnecting, cleaning, and reseating the harness resolves many F.32 cases that look like motor failure. -
Engineer step: spin by hand.
With power off, the fan should spin freely with light resistance.
Stiff or grinding rotation = bearing failure.
Replacement fan assemblies are 150-300 GBP plus engineer labour. -
Engineer step: PCB diagnosis.
If fan, harness, and flue all check out, the PCB driver section has failed.
Boards are 200-400 GBP and must match the boiler's serial range — not all are interchangeable. -
Reset after repair.
Press the reset button on the front of the boiler.
The unit attempts ignition.
Watch the fan during start-up — it should spin up smoothly to commanded speed within seconds.
Frequently Asked Questions
Will the boiler still produce hot water with F.32?
No — without correct combustion airflow the burner cannot fire safely.
The boiler locks out completely until the fan fault is resolved.
You will have no heating and no hot water until repair.