High
OVERHEAT LOCKOUT on Potterton Promax FSB 30HE

Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage to its internal components.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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 * Off. Possible causes: Flow pipe thermostat (stat) failure, fan stat failure, thermistor (red sensor on flow pipe) failure, combustion chamber door seal damaged, or PCB 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.

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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