Blocking error Medium

Gledhill Blocking error Fault Code

Also written as BLOCKINGERROR — same fault.

The Gledhill Blocking error fault code means: your boiler has paused operation because it has detected a temporary issue that is currently preventing it from running safely or efficiently.. It appears on 1 Gledhill model in our database.

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.

Technical description: ON : Blocking error OFF : Normal operating mode
Typical repair cost £100-£280 (including labour)

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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Gledhill models that show the Blocking error fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Gledhill Blocking error fault code information on this page is sourced and cross-checked against the official Gledhill service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026