Low
P.04 on Glow-worm Ultimate3 Combi

Your boiler has entered a temporary testing mode used by engineers to check its performance, which will automatically stop after 15 minutes.

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

Chimneysweepfunction:Ifthereisadomestichotwaterdemand,theproductrunsindomestichotwatermodeandatmaximumheatinput.Ifthereisnodomestichotwaterdemand,theproductrunswiththepartialheatloadthatissetviadiagnosticscoded.00andinheatingmode.Thefunctionisactivefor15minutes.

From this model's manual
Verified against the Glow Worm Ultimate3 Combi installation & service manual, page 40.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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