Medium
Block 11 on Atag Q 30CR

Your boiler has paused the heating because it cannot move water through your radiators fast enough, likely due to a blockage or closed valves.

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

Maximum ΔT of flow and return sensor in central heating has repeatedly been exceeded. During the block normal operation of the hot water supply is possible. The pump continues to operate at minimum capacity during the block.

From this model's manual
Verified against the Atag Q 30cr installation & service manual, page 39.
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 open.Ensure your system pressure is set correctly, usually between 1.0 and 1.5 bar.Check for any signs of a stuck pump or sludge buildup in the system pipes.

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