Medium
S.53 on Glow-worm Flexicom 24c / 28c

Your boiler is temporarily pausing its heating cycle because it has detected that the water flow through your radiators is not moving as it should.

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

The product is within the waiting period of the modulation block / operating block function as a result of low water pressure / water deficiency (flow/return spread too large).

From this model's manual
Verified against the Glow Worm Flexicom 24c 28c installation & service manual, page 46.
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

Check that all radiator valves throughout your home are fully openEnsure your system pressure gauge is reading between 1 and 1.5 barWait 15 minutes for the boiler to automatically reset itself once the flow improves

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