BoilerFaultCodesRavenheat E43 Fault Code
The Ravenheat E43 fault code means: your boiler has detected an unusual temperature difference between internal parts, suggesting that water is not circulating correctly through the system.. It appears on 9 Ravenheat models in our database.
Technical description: Different temperature error
What causes the Ravenheat E43 fault?
This fault occurs when the boiler detects a significant temperature gap between different sensors, which usually means water is trapped and overheating in one spot. The most common reasons are a failed pump that isn't moving the water or a blockage in the heat exchanger that is restricting flow. It can also be caused by a build-up of air or sludge within the system pipes.
This issue often appears when the heating is first turned on in autumn, as circulation pumps can seize up after being inactive throughout the summer.
DIY fix possible
Check that your system pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openTry resetting the boiler to clear the temporary sensor glitch
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ravenheat models that show the E43 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat E43 fault code information on this page is sourced and cross-checked against the official Ravenheat service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026