central heating system

Now that the cooler weather has arrived, we turned on our central heating system to find nothing! The boiler which suppliers the hot water and CH works fine for the hot water but when adjusting the thermostat to click the CH on, the boiler does not \\\"fire up\\\". So the radiators do not get warm. Note that the pump was replaced this year with a new grundfos pump.

As always ore information will be needed to isolate the problem. For general info to start with, what is the boiler model? do you have one pump that runs the DHW and the CH? If so, the pump sounds OK. also if so, it points to the diverter valve (if you have one. These are common failures. It will probably have a lever sticking out of the head at one end. Push he lever to the other end of its slot, and click it into its latched position. With CH demanded, does the boiler now start? If so, motor in head may have gears stripped.