I'm not too familiar with technical terms, so I'll try and lay out my problem as simply as possible...
I have a relatively modern boiler, but an old baseboard heating system. The thermostat (which for some reason was pulled out by the previous owner prior to sale) is a 2-wire system.
I bought a 2-wire (120V) Honeywell programmable thermo and hooked it up. The boiler works fine (we have hot water). However, the circulator will not run when the thermostat is hooked up. The motor begins to turn, then it cuts out and the thermostat resets.
Here's the strange thing from my standpoint... if I just manually complete the circuit with the two wires, the circulator runs fine and the baseboards heat up. Is the thermostat just defective?? Or am I using the wrong type? I bought a Honeywell 120-240 model from Home Depot. I don't have the model number on me, but it seemed to be the right choice.