E118
Potterton fault code
Potterton E118: low water pressure (below 0.5 bar)
You can usually fix this
The water pressure in your heating system has fallen too low. Baxi's fault table, which covers Potterton Assure, defines E118 as pressure below 0.5 bar.
Recommended pressure when cold for Potterton boilers: 1.0 to 2.0 bar.
What you can safely do
- Let the system cool and read the pressure gauge.
- Top up through the filling loop as your user guide describes, to the normal operating pressure of 1.0 to 2.0 bar that Baxi gives.
- Close the filling loop fully and reset the boiler if needed.
Call a Gas Safe engineer if
- The pressure keeps dropping after you top it up.
- You can see water leaking.
Find a Gas Safe engineer near you
Opens the official Gas Safe Register search.
Applies to: Potterton Assure (in Baxi's fault table). Codes can differ between models, so check your manual.