We recently purchased a two-story house with two heating zones (baseboard hot water). Unfortunately, it appears that the zones are wired together. No matter which thermostat kicks on, both circulating pumps come on, and we have heat coming on both floors. I did use a circuit tester to check, and yes, both pumps do come on together all the time. Each pump has its own box that controls it (where the thermostat wire comes in). I believe this is the source of the problem. Each box has six terminals, labeled 1-6. Can anyone tell me where these wires SHOULD go? The hot terminals that go to the pump are actually double-tapped, with a second wire heading to the furnace, which I think is the problem. Please help - thanks!
Each t-stat should go to it'sown pump relay. Line voltage the same, to each pump relay. Once the t-stat calls, only one box should come on and energize only 1 pump. Sounds like either the t-stats are possibly shorted in the wall and bringing on the pumps together or the pumps themselves are wired together. Where the lo voltage wire comes into the box, Disconnect and cross the terminals. You will be acting as the t-stat to make the pump relay come on.