What does the Baxi 433 fault code mean?

Your boiler has switched itself off because it has become too hot inside, likely due to water not circulating properly.

How much does it cost to fix Baxi error code 433?

Typical repair cost for the Baxi 433 fault is £120-£350 including labour.

Check that your radiator valves are fully open

Heat exchanger temperature exceeded (greater than 95 degrees)

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.

Safety-critical — turn off, read this.