I have a open vented system where my rads are heating up when only the hot water is on. My 3 way valve is either stuck or not working although it once was. It is not electrical as I can see the spring trying to move. My question is do I drain down the whole system from the bottom most rad and will that allow me to crack the pipes and inspect/change the valve? Do I also have to drain my hot water tank or will draining from the bottom rad be enough. I have heard that these can stick but I cant see away of taking off the solonoid without removing the whole unit.
Thanks for any help.
Stu