High
NOT OPERATING IN HEATING MODE on Johnson Starley Warmcair DW

Your boiler is receiving power but fails to respond when the heating is scheduled to turn on, likely due to a communication failure between the controls and the unit.

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

Heating timed terminal, programmer, MAF Stat, or Aquair PCB SL issues.

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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