73 Medium

Firebird 73 Fault Code

The Firebird 73 fault code means: your boiler has detected that the water being sent to one of your heating circuits is getting hotter than it should be, so it has safely paused the heating to prevent damage.. It appears on 1 Firebird model in our database.

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.

Technical description: Mixing over-temperature limit protection for mixed circuit - Circuit 2 supply temperature > Target temperature + offset
Typical repair cost £150-300 (including labour)

Engineer required

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

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Firebird models that show the 73 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Firebird 73 fault code information on this page is sourced and cross-checked against the official Firebird service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026