i have a central heating system, wall mounted gas boiler downstairs, hot water tank upstairs and header tanks in the roof.
the heating system has two honywell motorized valves, two port that both look a little old.one valve for hot water and one for central heating The hot water heats fine, boiler & pump kicks in when required. the central heating however will now not work on its own, it has been doing so until 2 days ago. if i run hot water out of the hot tank the boiler & pump will start and run ok, the hot water motorized valve opens but at the same time the rads will heat up. when the hot water in the tank is back up to tempature everything stops but the central heating motorized valve is still open but pump does not work. the central heating motorised valve is definitly working and opening, water would not circulate around the rads otherwise. when i turn the room thermostate off the central heating motorized valve closes, turn the thermostate up the valve opens. when i turn the heating off on the electronic timer the valve closes, turn it back on and the valve re-opens. the pump is a Grunfoss and this is working fine with the hot water. it is on the fastest pump setting and runs very quietly. i can only deduce that either the central heating motorised valve or the electronic timer unit is not sending a "message" for the pump to run or the boiler to fire.
can anyone help please
the heating system has two honywell motorized valves, two port that both look a little old.one valve for hot water and one for central heating The hot water heats fine, boiler & pump kicks in when required. the central heating however will now not work on its own, it has been doing so until 2 days ago. if i run hot water out of the hot tank the boiler & pump will start and run ok, the hot water motorized valve opens but at the same time the rads will heat up. when the hot water in the tank is back up to tempature everything stops but the central heating motorized valve is still open but pump does not work. the central heating motorised valve is definitly working and opening, water would not circulate around the rads otherwise. when i turn the room thermostate off the central heating motorized valve closes, turn the thermostate up the valve opens. when i turn the heating off on the electronic timer the valve closes, turn it back on and the valve re-opens. the pump is a Grunfoss and this is working fine with the hot water. it is on the fastest pump setting and runs very quietly. i can only deduce that either the central heating motorised valve or the electronic timer unit is not sending a "message" for the pump to run or the boiler to fire.
can anyone help please