P35 Low

Alpha P35 Fault Code

The Alpha P35 fault code means: your boiler is temporarily waiting to start because it is part of a larger heating system setup where multiple units are programmed to ignite in a specific sequence to avoid overloading the system.. It appears on 2 Alpha models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Cascade delay

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Alpha models that show the P35 fault code

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

Source

Alpha P35 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 7 July 2026