E42 Medium

Alpha E42 Fault Code

The Alpha E42 fault code means: your boiler's control panel has detected that one of the buttons on the front display is being held down or is stuck in the pressed position.. It appears on 5 Alpha models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Button stuck
Typical repair cost £90-180 (including labour)

DIY fix possible

Switch off the power supply to the boiler at the fused spur or mains switch.Inspect the front control panel buttons to ensure none are visibly depressed or jammed with debris.Gently press and release each button several times to ensure they move freely and 'click' normally.Switch the power back on and see if the error clears.

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Alpha models that show the E42 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha E42 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026