BoilerFaultCodesPotterton E135 Fault Code
The Potterton E135 fault code means: your boiler's internal computer has encountered a software glitch or a communication failure that is preventing it from starting up safely.. It appears on 2 Potterton models in our database.
Technical description: Internal error
What causes the Potterton E135 fault?
This fault occurs when the boiler's main control board experiences a critical internal failure or loses the ability to talk to other sensors. It is essentially a software crash where the 'brain' of the boiler can no longer verify that it is safe to operate. This is usually caused by a component failure on the circuit board itself or a loose connection in the internal wiring.
DIY fix possible
Locate the reset button or turn the selector switch to the reset positionHold for five seconds and releaseWait two minutes to see if the boiler restarts and the code clears
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Gas Safe Register →Potterton models that show the E135 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E135 fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026