BoilerFaultCodesECA F43 Fault Code
The ECA F43 fault code means: your boiler has tried to top up its internal water pressure automatically but failed, meaning there is not enough water in the system to operate safely.. It appears on 3 ECA models in our database.
Technical description: Low Water Pressure After Auto Water Filling Fault (blocking) — water filling valve may have failed or mains water pressure insufficient; notify ECA authorised service
DIY fix possible
Check that your main water supply stopcock is fully openEnsure there are no visible leaks from radiators or pipeworkTry to manually increase the system pressure to 1.5 bar using the filling loop if accessibleReset the boiler once the pressure is restored
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like F43: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
ECA models that show the F43 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
ECA F43 fault code information on this page is sourced and cross-checked against the official ECA service / installation manuals for each affected model.
- ECA Confeo Premix HCH manual (PDF)
- ECA Confeo Premix HM manual (PDF)
- ECA Confeo Premix HST manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026