BoilerFaultCodesRavenheat E41 Fault Code
The Ravenheat E41 fault code means: your boiler has sensed an unusual temperature difference between the water leaving it and the water returning, suggesting that water is not circulating through your heating system correctly.. It appears on 9 Ravenheat models in our database.
Technical description: Different flow/return temperatures
What causes the Ravenheat E41 fault?
This fault occurs when the boiler detects that heat is not being carried away from the unit quickly enough, often due to a pump failure or a blockage in the pipework. It physically happens because the water exiting the boiler is significantly hotter than the water coming back, suggesting the flow has slowed down or stopped entirely. The most common reasons are a seized circulation pump or a buildup of sludge and debris within the main heat exchanger.
This issue often surfaces at the start of autumn when heating systems are turned back on after sitting idle all summer, which can cause internal pump components to seize.
DIY fix possible
Check that all radiator valves (TRVs) are fully openEnsure your system pressure is topped up to roughly 1.5 barBleed all radiators to remove trapped air locksRestart the boiler using the reset button
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Gas Safe Register →Ravenheat models that show the E41 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat E41 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