Heating, Air Conditioning, Fridge, HVAC/zone valve control wiring



I currently have a 2 zone hot water baseboard system with a Utica boiler in my home.  I want to install and outdoor reset control to make it more energy efficient.  Utica recommended the Argo DPM2 outdoor reset along with the AZ3 zone valve control panel.  

In looking at the wiring instructions on both I think I'm comfortable with most everything.  The only question I have is on the zone valve control where there is wiring for 2 end switches (x1, x1 and x2, x2#.  For the X1, that comes right from the outdoor reset so I'm fine with that but the X2 looks like it controls the circulator pump (line voltage?).  

My question is how exactly is the 2nd end switch wired?  It appears that the hot goes right from the power to the zone control panel and the neutral goes from the pump to the zone control panel.  Does this make sense?  Thw wiring diagram I'm referring to is on Page 9 of the install sheet if that helps.  http://www.ecrinternational.com/secure/upload/document/1549.pdf



The wiring diagram shows L1 goes to the switch, out of the switch then to the pump.  The pump neutral goes directly to neutral or L2.  It is much like a light works on a switch.

Beware that the pump might exceed the rating of the switch.


Heating, Air Conditioning, Fridge, HVAC

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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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