Hi. We have just moved into a house with a oil fired heating system. When we moved in the cylinder thermostat and associated valve had no electrical supply. The water coming from the hot taps was extremely hot and heating seemed OK. I connected the cylinder thermostat (set to 60C). The thermostat itself seems to be switching and the drive for the mechanical valve is operational. I checked the valve moves realtively freely and put everthing back together. Next morning there was no hot water! By the evening there was (it has been sporadic ever since). I have subsequently removed the valve motor and placed the valve in a half open/half closed position - this seems to have remidied the situation for the moment. The water coming from the taps is now not as hot as before.
Any thoughts on why the thermostat and valve drive would have been disconnected?
Would this have caused the initially very hot tap water and the subsequent lack of hot water?
Do I need to change the thermostat, drive and valve and is this straightforward?