E118 High

Baxi E118 Fault Code

The Baxi E118 fault code means: your boiler has stopped working because the water pressure in the system has dropped too low.. It appears on 16 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: Water pressure too low / System refill required

What causes the Baxi E118 fault?

This fault occurs when the water pressure inside your heating system drops below the minimum level required for the boiler to operate safely. The most common reasons are a slow leak from a pipe or radiator valve, or air being bled from the radiators without the system being topped back up with water.

This fault is frequently seen in autumn when homeowners turn their heating back on for the first time and find the pressure has gradually depleted over the summer months.

Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the filling loop (usually a silver braided hose with small lever valves under the boiler).Slowly open both lever valves to allow water into the system.Watch the pressure gauge and close both valves firmly once it 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 31 August 2026