How much does it cost to fix boiler error code 5.iv?

Typical repair cost for the boiler 5.iv fault is £90-180 including labour.

5.iv High

Boiler Fault Code 5.iv

Also written as 5IV — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 5.iv appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to heat your water at the correct temperature because an internal component responsible for controlling air flow is the wrong type for this specific model. (As reported on Chaffoteaux Celtic 24 HE)

Pick your boiler brand for the 5.iv fix

Chaffoteaux 5.iv 3 models

Source

Information for the 5.iv fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026