BoilerFaultCodesKeston E19 Fault Code
The Keston E19 fault code means: your boiler has stopped working because the water returning to the unit is too hot, typically meaning the heat isn't being moved away into your radiators effectively.. It appears on 7 Keston models in our database.
Technical description: Maximum return temperature exceeded – check circulation
DIY fix possible
Ensure all radiator valves (TRVs) are turned to the highest settingCheck that the internal boiler pump is running if accessibleCheck that all external zone valves or isolation valves are fully openBleed all radiators to remove trapped air that might be blocking water flow
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Gas Safe Register →Keston models that show the E19 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Keston E19 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