How much does it cost to fix boiler error code pressure difference < 0.9 mbar?

Typical repair cost for the boiler pressure difference < 0.9 mbar fault is £120-280 including labour.

pressure difference < 0.9 mbar High

Boiler Fault Code pressure difference < 0.9 mbar

Q: What does the boiler pressure difference < 0.9 mbar fault code mean?

Your boiler is unable to safely clear exhaust gases, which is preventing it from firing up to provide heating or hot water.

Q: How much does it cost to fix boiler error code pressure difference < 0.9 mbar?

Typical repair cost for the boiler pressure difference < 0.9 mbar fault is £120-280 including labour.

Also written as PRESSUREDIFFERENCE09MBAR — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code pressure difference < 0.9 mbar 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 unable to safely clear exhaust gases, which is preventing it from firing up to provide heating or hot water. (As reported on Ideal Classic NF)

Pick your boiler brand for the pressure difference < 0.9 mbar fix

Ideal pressure difference < 0.9 mbar 1 model

Source

Information for the pressure difference < 0.9 mbar 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