Technical description
No CH Operation
What causes this fault?
This fault occurs when the boiler is receiving a signal to provide hot water but is failing to recognize or act on the command to heat your radiators. The most common reason is a failure in the communication between your external room thermostat and the boiler, or a mechanical failure of the internal valve that directs heat to the central heating circuit.
This fault is most frequently noticed during the first cold spell of autumn when homeowners switch their heating back on after it has been inactive all summer.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.