BoilerFaultCodesRemeha E15 Fault Code
The Remeha E15 fault code means: your boiler has shut down because it thinks the water returning from your radiators is hotter than the water leaving the boiler, which suggests a sensor error or a circulation problem.. It appears on 8 Remeha models in our database.
Technical description: Return temperature higher than flow temperature
What causes the Remeha E15 fault?
This fault occurs when the boiler's internal sensors detect that the water coming back from your heating system is hotter than the water it just sent out, which is physically impossible during normal operation. The most common reason is that one of the temperature sensors has failed or 'drifted' out of calibration, though it can also be triggered by a pump failure or a significant blockage that has completely stopped water from circulating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Remeha models that show the E15 fault code
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Source
Remeha E15 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