What does the Baxi H.01 – .21 fault code mean?

Your boiler is heating up too quickly when you turn on the hot water, causing it to shut down to prevent overheating.

How much does it cost to fix Baxi error code H.01 – .21?

Typical repair cost for the Baxi H.01 – .21 fault is £120-280 including labour.

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

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Almost always a stuck diverter valve on combis.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.