“Electronic boiler controllers have a circulator holdoff function that prevents the circulators from running until the boiler reaches a minimum operating temperature. This can be accomplished by activating the ZC/ZR relay in the 3-zone switching relay by a 120 VAC signal from the boiler control. If this feature were provided on the Taco switching relay, then the circulator enable signal on the boiler control would not have to carry the load current of multiple circulators. Also, the circulator relays on the Taco unit look a little light to handle the inrush current of a B & G series 100 pump.”
