E118 High

Baxi E118 Fault Code

The Baxi E118 fault code means: your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.. It appears on 24 Baxi models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Primary system water pressure too low (< 0.5 bar).

What causes the Baxi E118 fault?

This fault occurs when the water pressure inside your heating system drops below a safe level, causing the boiler to shut down to prevent internal damage. The most common reasons are a slow leak from a radiator valve or pipework, or air being released from the system through the radiators or an internal auto-air vent.

This issue often appears when you turn your heating back on after summer, as the change in temperature can reveal small leaks or trapped air in the pipes.

Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the filling loop (usually a silver braided hose with two blue-handled valves) underneath the boiler.Slowly open both valves until you hear water entering the system.Watch the pressure gauge and close both valves firmly once the needle reaches between 1.0 and 1.5 bar.

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Baxi models that show the E118 fault code

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

Source

Baxi E118 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

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