BoilerFaultCodesHalstead Erroneous APS signal Fault Code
Also written as ERRONEOUSAPSSIGNAL — same fault.
The Halstead Erroneous APS signal fault code means: 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.. It appears on 1 Halstead model in our database.
Technical description: Missing or defective APS signal • Check APS • Check pipe connections for blockage • Check fan • Check PCB • Check flue condition
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Halstead models that show the Erroneous APS signal fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Halstead Erroneous APS signal fault code information on this page is sourced and cross-checked against the official Halstead service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026