BoilerFaultCodesRemeha E20 Fault Code
The Remeha E20 fault code means: your boiler is overheating because the water isn't moving through the system fast enough to cool it down.. It appears on 1 Remeha model in our database.
Technical description: Difference between flow and return temperature too high: check pump and flow rate.
What causes the Remeha E20 fault?
This fault occurs when the water inside the boiler gets too hot because it isn't moving away into your radiators quickly enough. The most common reasons are a failing pump that can't push the water, or a buildup of sludge and scale that has physically blocked the internal pipes. When the temperature difference between the water going out and coming back becomes too large, the boiler shuts down for safety.
This fault is frequently seen at the start of autumn when heating systems are switched back on after being idle all summer, which can cause internal pump components to seize.
DIY fix possible
Check that your radiator valves are openEnsure the system pressure is between 1 and 1.5 barRestart the boiler to see if the pump clears a temporary blockage
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Gas Safe Register →Remeha models that show the E20 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha E20 fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026