High
321 on Baxi Ecoblue Advance Combi

Your boiler is struggling to detect the temperature of your hot water supply, which means it has stopped providing hot water to prevent overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Hot Water NTC Fault

From this model's manual
Verified against the Baxi Ecoblue Advance Heat installation & service manual, page 64.
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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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