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Circulator Zone Not Engaging the Boiler
I am trying to help a friend diagnose his heating system. It is a three zone, circulator system with a Taco Control. One zone wasn't getting the cast iron radiators warm. Initial thought was to bleed the radiators (which resulted in a lost radiator pin and water shooting over the livingroom floor). Fixed that, got pressure back up in the boiler but still no warming. Time to look at the controls. The 24V thermostat that controlled the zone was removed and the wires crossed and the pump started, the boiler engaged and the radiators began to get warm. A trip to the trusty big box, a new thermostat was obtained, and the R and W wires connected to the appropriate positions. Turned up the set point and .... nothing the boiler didn't fire and the circulators didn't apparently operate. (Although I am not 100% sure on the last point since this was a phone diagnosis). Two bad thermostats? Thoughts to try next?