Emergency
Earth Fault on Potterton Suprima

Your boiler has detected that the internal electrical wires for the live and neutral supply have been reversed during installation or a recent repair.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Mains Reversal

Shared across the Suprima range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s 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 emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 9 fault codes on the Suprima

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

BlockingBoiler Temperature Control SatisfiedExt. Call for Heat (Boiler set to STNDBY, Temp. Control set to 'O' Off)Ext. Call for Heat (STNDBY switch to ON, Temp. Control set to Max.)FLAME DetectedIgnition (i.e. Gas and Sparks ON)LockoutMains ON Only

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