Just started looking for a fault on my Y plan system - the water is too hot and does not respond to the cylinder stat.
I've noticed that although the cylinder stat is turned down ( not calling for heat ), when the CH stat is turned up ( calling for heat ) both systems are heated ( rads and hot water ).
My first assumption is that the mid position valve is not closing the HW port when the cylinder stat is satisfied, allowing the flow in both directions and overheating the hot water.
Before I change the valve, has anyone got any other suggestions or things that should be checked.?
The programmer has been changed for another fault (battery faulty) and also the pump (seized). The valve did get very hot when the pump seized and I'm just wondering whether this has caused it to stick etc.
I've noticed that although the cylinder stat is turned down ( not calling for heat ), when the CH stat is turned up ( calling for heat ) both systems are heated ( rads and hot water ).
My first assumption is that the mid position valve is not closing the HW port when the cylinder stat is satisfied, allowing the flow in both directions and overheating the hot water.
Before I change the valve, has anyone got any other suggestions or things that should be checked.?
The programmer has been changed for another fault (battery faulty) and also the pump (seized). The valve did get very hot when the pump seized and I'm just wondering whether this has caused it to stick etc.