How much does it cost to fix boiler error code Heating demand light ON?

Typical repair cost for the boiler Heating demand light ON fault is £120-200 including labour.

Heating demand light ON High

Boiler Fault Code Heating demand light ON

Also written as HEATINGDEMANDLIGHTON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Heating demand light ON appears across 1 boiler brand and 4 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is confused because a sensor that measures the temperature of your heating water has stopped sending the correct signal, so it has turned off the heating to stay safe. (As reported on Ferroli Falcon)

Pick your boiler brand for the Heating demand light ON fix

Ferroli Heating demand light ON 4 models

Source

Information for the Heating demand light ON fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026