BoilerFaultCodesRemeha C0 Fault Code
The Remeha C0 fault code means: your boiler is working correctly and is simply waiting for a command from your thermostat to start heating.. It appears on 2 Remeha models in our database.
Technical description: Boiler is stand-by
What causes the Remeha C0 fault?
This is not a fault, but rather a status message indicating the boiler has finished its previous task and is resting. It occurs when the water inside the unit has reached the required temperature and the boiler is now waiting for a signal from your room thermostat or timer to start up again. Essentially, the system is in a 'ready' state and is powered on, but there is currently no demand for heating or hot water.
This code is more visible during the summer or shoulder months when your thermostat is likely turned down and the boiler spends more time idle.
DIY fix possible
Check if your room thermostat is turned up high enough to trigger heatingEnsure your heating programmer or timer is set to an 'On' periodCheck that your thermostatic radiator valves are open
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Gas Safe Register →Remeha models that show the C0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha C0 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