Medium
Blocking error on Gledhill GB35C

Your boiler has paused operation because it has detected a temporary issue that is currently preventing it from running safely or efficiently.

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

ON : Blocking error OFF : Normal operating mode

From this model's manual
Verified against the Gledhill Gb35c installation & service manual.
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 if your system water pressure is between 1 and 1.5 barEnsure all radiator valves are open to allow water flowPress and hold the Reset button for 5 seconds to clear the block

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