From my limited understanding a central heating failure could be the result of any one of a number of things misbehaving. If the HW is working, it seems likely the boiler is functioning properly.
The room thermostat (I assume just one) needs to send a signal to the boiler that the temperature is below that set to enable the boiler to fire up.
The boiler may have a water temperature sensor for the central heating circuits in addition to the hot water on a separate circuit.
There will be a valve in the system which allows the HW to operate independently of the CH. These can seize which you may be able to free off or lubricate.
The pump may have failed - the hot water may still be OK if the tank is gravity fed.
|