High
FAN LOCKOUT on Potterton Promax FSB 30HE

Your boiler's fan, which safely clears exhaust gases from the unit, has stopped spinning correctly and prevented the system from firing up.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Lights: On * * Off. Possible causes: Fan wiring continuity fault, fan PCB connection failure, or fan failure.

From this model's manual
Verified against the Potterton Promax Fsb 30he installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's control board tries to start the fan but doesn't receive the correct signal that it is spinning at the right speed. The most common reasons are a build-up of debris causing the fan to seize or an electrical failure within the fan's motor or the main circuit board. Without the fan running correctly, the boiler cannot safely remove exhaust gases, so it shut downs for safety.

This fault is more common in winter, as the fan has to work much harder and for longer periods during cold spells, which can cause older motors to fail.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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