I hate oil heat, and try to keep it shut off 90% of the time, and rely on my pellet stove, so...... I have one zone that for the past few days, the register is always warm with the forced hot water heat. I cranked the thermostat down to the lowest, 50 degrees, and still I can feel that the register is warm. When I crank the register up to the highest, the boiler kicks on, and the circulator pump starts running, like it should. I have two other zones, and those registers are cold. The small circulaltor pump for this zone is not on. The motor is not running, but the pipes are warm to hot. The warm water from the boiler is feeding this zone. So, I googled this problem, and alot of people seem to say that some valve is stuck open, but my question is, where is this valve? Is it something I can fix on my own? The pipe leaves the boiler, and there is no valve that I can see. Only the pump, and a faucet relief valve. Any ideas on how to fix this? Or, do I need a repairman?