Gas central heating - what could it be?

[jodiejordash]

My central heating is not working - although it is still heating the hot water, the boiler is not firing up for the radiators - could it be the thermostat?

[smurfchops]

Can you turn up the boiler at the thermostat? We have a thermostat on the boiler and another one in the dining room - one may be switched too low.

[stanleyman]

The most likely cause is a failed syncron motor in the motor valve controlling the heating. You will have one, three port valve or two, two port valves. This is usually one or two small silver boxes with a lever on the side. You can use this lever to lock open the valve to get the heating going until the motor can be replaced but you will lose thermostatic control.

[spinchimp]

When this happened to me it was the pump. Had to be replaced.