DEMAND LIGHT ONLY Low

Worcester Bosch DEMAND LIGHT ONLY Fault Code

Also written as DEMANDLIGHTONLY — same fault.

The Worcester Bosch DEMAND LIGHT ONLY fault code means: your boiler is correctly telling you that it has already reached the temperature you asked for and is simply waiting for the water to cool down before heating it up again.. It appears on 2 Worcester Bosch models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: It is normal to see only a demand light if the boiler is hot and the burner has temporarily shut off. If boiler is cool, suggests sensor or control board fault.

Engineer required

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

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Worcester Bosch models that show the DEMAND LIGHT ONLY fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch DEMAND LIGHT ONLY fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

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