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Nest Gen3 thermostat on cool only mode kicks on AC along with the emergency heat

rickdog72
Community Member

Thanks for anyone taking the time to help me out on this, it's been driving me nuts. 

So I had a new system put in 3 years ago. And from day 1 it had a Nest Gen 3 making everything work. My setup is a 2 stage A/C + Heatpump setup and a boiler that does radiant heat as a back up when the temp reaches ~40F. 

My problem isn't with the heat / two stage setup, or at least I don't think. 

My problem is if I have my boiler wires hooked up during AC season (even with my nest set to cool only), my unit is turning on the AC + my boiler at the same time so I get a nice blast of heat from the radiant mixed with nice cool air from the vents.   

I don't understand how this can happen, but I'm nearly 100% sure it's wiring or electrical.  

I'll attach my boiler and my wire setup at the Nest. I have tried resisters, but they didn't work when I put them on the boiler side between C and W.  Zone 2 is the the nest that isn't working. Boiler zone 2 is the one not workingBoiler zone 2 is the one not workingTwo stage A/C with heat pump and boiler backup *emergency heat below 40FTwo stage A/C with heat pump and boiler backup *emergency heat below 40F

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