I have a Weil-McLain hot water boiler for baseboard heat. The system has one circulator pump. The system has 5 zones - 3 work fine and two are not working. All the zone valves and thermostats are Honeywell and have 2 wires going to the thermostats. For problem zone #1, when the thermostate is raised the zone valve opens but the boiler does not fire. I know the zone opens because I can hear it open with my ear next to the valve and the room gets heat, but only when another zone is turned on to get the boiler turned going. For problem zone #2, nothing happens when the thermostat is raised - zone valve does not open (no noise can be heard from the valve at all) and boiler does not fire. I checked the wiring and all zones are wired the same, with two zones going to the boiler through one transformer and the three others going through a second transformer. I thought that I might have a bad transformer that was causing the boiler to not fire, but one of the zones that does cause the boil to fire is wired through the same transformer as the two that don't work. I'm inclined to believe that the "problem zone #2" (the one that doesn't work at all) has a bad zone valve that needs to be replaced, but that won't address the issue with the boiler not firing. I have replaced all 5 thermostats, but still have the same problem with these two zones.