2 Thermostats - 1 for CAC & 1 for Gas Heat .... 1 nest or 2 nests?

Old 04-20-18, 02:03 PM
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Question 2 Thermostats - 1 for CAC & 1 for Gas Heat .... 1 nest or 2 nests?

I purchased my house in July and recently received a nest learning thermostat as a gift. I can't seem to find an answer that directly relates to my situation anywhere so I thought I would ask for help from some experts

Summary of questions: Can I combine 2 thermostats to 1? Is it worth doing? Or should I just get 2 nests?

The house has 2 thermostats on perpendicular walls (opposite side of these enclose the back and a side of my closet). 1. Turn dial thermostat for heat (gas fired hot water boiler - Weil Mclain model CGM 5 PL series 8). 2. Programmable thermostat about 3 feet away (on the wall perpendicular to the wall with the heater thermostat) for the central air conditioner (Rheem moel 13AJN36A01).

My first question is 2 part: Why would they install two thermostats rather than put them both on the same thermostat in the first place. My belief is the central air system was added well after the current heating system so i'm not sure why the two weren't controlled by the same thermostat once the CAC was installed. And can this even be done? I would think it should be as easy as cutting into the wall from my closet and rerouting the wires from the heat thermostat to the AC thermostat.

My next question: If this IS possible, how much would this cost? Am I better off just purchasing a second nest for $200?

Last question which is specific to those who have experience with the nest - will having two nests, each for their own temperature cause conflict? If this is the route to take I plan on starting with replacing the nest for the heat (since spring/summer has been delayed here in the northeast) and since the CAC thermostat in place now is programmable.

Thank you in advance!!!
Old 04-20-18, 02:10 PM
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Your boiler system might have 2 zones.
Old 04-20-18, 03:07 PM
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Some a/c installers know nothing about hot water systems so don't want to touch even the controls.

If normal thermostat wiring then they can easily be combined by running a new cable and splicing in.

Two Nests will be mostly independent except for sharing the away function.
Old 04-20-18, 09:53 PM
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Welcome to the forums.

With a round thermostat we can assume only two wires are on it.
We need to know what for wiring is on the cooling thermostat.
Tells us the color and the terminal it's on.

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