Baxi E118 Fault Code: Water Pressure Low Guide
The E118 fault code on a Baxi boiler means the water pressure is low (below 0.5 bar).
What the E118 fault code means
The E118 code is a low water pressure warning. Your Baxi boiler needs water pressure between 1.0 and 1.5 bar to operate. When the pressure drops below 0.5 bar, the boiler shuts down to protect itself.
Possible causes of the E118 fault
- Water pressure below 0.5 bar — The system has lost significant water.
- A leak in the system — Water is escaping from a radiator, pipe, or the boiler itself.
- Recently bled radiators — Bleeding releases air and some water, dropping the pressure.
- Faulty pressure sensor — The sensor may be giving incorrect readings.
Can you fix it yourself?
Yes — in most cases. The E118 fault is one you can usually fix:
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Check the pressure gauge — If it reads below 1.0 bar, the system needs repressurising.
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Repressurise the system — Use the filling loop (usually a silver braided hose with two valves under the boiler). Slowly open both valves and watch the pressure gauge. When it reads 1.5 bar, close both valves.
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Reset the boiler — After repressurising, reset the boiler. The E118 code should clear.
If the pressure keeps dropping after repressurising, you have a leak — call a Gas Safe registered engineer to find and repair it.
Need help with your Baxi boiler?
Sanju's Heating covers Newbury, Basingstoke and Reading. Call us on 01635 74 50 40 or book online at sanjusheating.co.uk/book
Check our full Baxi fault code guide for help with other Baxi error codes.
