High
H.01 – .21 on Baxi Netaheat

Your boiler is shutting down because it is heating up much too quickly when you turn on your taps, usually because the water isn't moving through the system properly.

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.

Technical description

Temporary error – flow temperature increasing too fast in domestic hot water (DHW) mode, insufficient circulation or sensor error.

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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