Medium Warning
D.44 on Vaillant ecoTEC

Your boiler's electronic system is struggling to correctly detect the flame signal, which could lead to it locking out for safety.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Digitised ionisation – potential error

What causes this fault?

This fault occurs when the boiler's internal computer receives an unstable or unexpected signal from the flame sensing components. It usually happens because the sensor that monitors the flame is dirty, worn out, or the electrical connection between the sensor and the main control board has become weak.

Engineer required

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

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Related fault codes

F.28View →F.29View →S.42View →

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