High
Erroneous APS signal on Halstead Finest Gold

Your boiler has stopped working because it cannot confirm that waste gases are being safely pushed out through the flue, which is a necessary safety step before it can fire up.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Missing or defective APS signal • Check APS • Check pipe connections for blockage • Check fan • Check PCB • Check flue condition

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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