Medium
P.01 on Vaillant Atmomax

Your boiler is currently stuck in a special high-performance testing mode and has failed to complete its internal check.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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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

Maximum load test program error

DIY fix possible

Press and hold the 'Reset' button (indicated by a flame with a line through it) for five seconds.Turn the boiler off at the main electrical isolation switch, wait 30 seconds, and turn it back on.Wait for the boiler to complete its startup sequence to see if it returns to normal operation.

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Related fault codes

P.02View →P.00View →

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