High
Overheat LOCKOUT on Potterton Promax Heat Only

Your boiler has detected that it has become too hot and has automatically shut itself down to prevent damage, requiring you to manually restart it.

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

Manual reset. The 'Lockout' (Red) light will flash. Occurs if an overheat condition occurs or the overheat stat is off.

From this model's manual
Verified against the Potterton/Potterton Promax He Store 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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Related fault codes

E119View →E125View →

All 24 fault codes on the Promax Heat Only

Seeing a different code? Every code this model can display, in one place.

Flash Flash OnFlash Off FlashFlash Off OnFlash On FlashFlash On OnIgnition LockoutLights: Flash Flash OnLights: Flash Off FlashLights: Flash Off OnLights: Flash On FlashLights: Flash On OnLights: Off Off OffLights: On Flash FlashLights: On Off FlashLights: On On FlashNo Switched LiveOn Flash FlashOn Flash OnOn Off FlashOn Off OnOn On FlashOn On OnPCB Fault

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