Medium
S.33 on Glow-worm Ultimate3 Combi

Your boiler is currently waiting for the air pressure inside the unit to balance out before it safely attempts to fire up your heating or hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Forcedfanoperationuntilthepressuremonitorisswitched

From this model's manual
Verified against the Glow Worm Ultimate3 Combi installation & service manual, page 45.
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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