Boiler Fan Not Running
The boiler tries to start, you hear a click, then it stops without the usual whoosh of the fan spinning up..
The boiler tries to start, you hear a click, then it stops without the usual whoosh of the fan spinning up.
What is actually going on
The boiler tries to start, you hear a click, then it stops without the usual whoosh of the fan spinning up.
The realistic causes, in order
A seized fan bearing, common where a boiler sits in a dusty loft or garage and has had years of intermittent duty A failed fan capacitor or open winding, so the fan draws current but never reaches the speed the PCB expects A PCB or wiring fault that never delivers the run signal, often at a corroded connector behind the case
What we test on site
Fan speed feedback against the manufacturer's expected RPM range for that model Supply voltage at the fan plug while the boiler attempts a start sequence The wiring loom and connector block for heat damage or green corrosion
Worth checking today if you have a boiler fan that won't run
- Listen at start-up — silence where you'd normally hear the fan is the useful clue to report
- Note the fault code on the display before switching the boiler off and on
- A boiler will not run its ignition sequence without proven fan operation, because the fan is what proves the flue can clear combustion products. Never bypass or override it.
Who does the work
- Gas Safe registered engineers — registration 554328
- Worcester Bosch accredited installer
- John The Plumb Ltd, company registration 10026483
Get a boiler fan that won't run diagnosed properly
Fans are stock items for common models, so this is usually a same-visit repair once the diagnosis is confirmed.
Questions we get asked
What causes a boiler fan that won't run on a gas boiler?
A seized fan bearing, common where a boiler sits in a dusty loft or garage and has had years of intermittent duty
What normally puts a boiler fan that won't run right?
Fans are stock items for common models, so this is usually a same-visit repair once the diagnosis is confirmed.
Is it safe to keep using the system with a boiler fan that won't run?
A boiler will not run its ignition sequence without proven fan operation, because the fan is what proves the flue can clear combustion products. Never bypass or override it.