BoilerFaultCodesKeston E37 Fault Code
The Keston E37 fault code means: your boiler has detected that the water pressure is too low, which has caused it to stop working to avoid damage.. It appears on 9 Keston models in our database.
Technical description: Water pressure error - You must top up the water pressure for your system
What causes the Keston E37 fault?
This fault occurs when the system lacks enough water to circulate safely, triggering a safety shutdown. The most common reasons are a slow leak in the pipework or radiators, or having recently bled your radiators without topping the pressure back up.
This is common in autumn when homeowners turn their heating back on for the first time and discover the pressure has naturally dropped over the summer.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Open the taps on the filling loop slowly until you hear water entering the system.Watch the pressure gauge and close the taps once the needle reaches 1.5 bar.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Keston models that show the E37 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Keston E37 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026