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

Typical repair cost for the boiler 4) fault is £150-300 including labour.

4) Medium

Boiler Fault Code 4)

Also written as 4 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 4) appears across 8 boiler brands and 20 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 switch between heating your radiators and heating your hot water tank, which may result in a lack of hot water. (As reported on Remeha Quinta 30)

Pick your boiler brand for the 4) fix

Atmos 4) 4 models Biasi 4) 2 models Daikin 4) 3 models Dimplex 4) 3 models Halstead 4) 1 model Maxol 4) 1 model Remeha 4) 5 models Worcester Bosch 4) 1 model

Source

Information for the 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 7 July 2026