How much does it cost to fix boiler error code Test 4?

Typical repair cost for the boiler Test 4 fault is £120-250 including labour.

Test 4 High

Boiler Fault Code Test 4

Also written as TEST4 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Test 4 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is failing to light the burner, meaning it cannot produce heating or hot water safely. (As reported on Vokera Hydra)

Pick your boiler brand for the Test 4 fix

Vokera Test 4 1 model

Source

Information for the Test 4 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