Low
S.02 on Glow-worm Energy

Your boiler is simply preparing to start the heating process by circulating water, and this is a normal part of its routine operation.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Heating mode: Pump pre-run

From this model's manual
Verified against the Glow Worm Energy installation & service manual, page 32.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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