Trying to upgrade to Nest thermostat

[dtbrown81]

Hi, I have a new Nest thermostat that I obtained with a rebate from our gas company.

The thermostat that I am replacing is an old Honeywell T87F2873 two wire, heat only mechanical thermostat.

Will I be able to use the Nest thermostat? I am not finding anything definitive on my situation and do not want to open the box before I find out.

Thanks

[CoolingWizard]

There is one overriding key factor that must be observed before you can use any thermostat that requires program ability or advance functionality. The control system must be a 24 V AC system. Sometimes furnaces, which are a two wire system are simply a connection from wire want to wire to will start the furnace. a nest thermostat that uses batteries would be OK. But if you use a nest learning thermostat second or third generation you’re going to run into problems with power. 

If you can go down to your furnace and take a picture of the manufacture label, I can look up the system and see if it uses 24 V AC for the gas valve control or if it’s using milliamps of power.

AC Cooling Wizard

[dtbrown81]

Thanks for the response. I think mine is the former - 24 V AC system. 

Here are a couple pics, including one of the zone valves. There is not a manufacturer label that I could find. I just have the basic Nest thermostat that has battery. 

front of furnace

 

side of furnace

 

[dtbrown81]

zone valve

 zone valve

[zoeuvre]

Hi dtbrown81, 

Thanks for reaching out to us. To check more for the compatibility of your system with our Nest Thermostats, please help us with an exact photo of your HVAC control board where the other end of your thermostat wires are connected. In most cases, the control board can be found at your furnace or air handler.

I'll look forward to your response. 

Thanks for your help, @CoolingWizard. 

Best,

Zoe

[dtbrown81]

Hi Zoe,

I thought that's what I included in my first response above?

zone valveside of furnacefront of furnace

The wires are split and connected to the zone valve (1st pic) and switch on side of furnace (2nd pic).

Thanks,

Dave

[zoeuvre]

Hi folks,

@dtbrown81, thanks for the follow-up. The HVAC control board is where the thermostat wires connect to your heating and cooling system. In most cases the control board can be found at your furnace or air handler.

Thanks,

Zoe

[zoeuvre]

Hey dtbrown81, 

I wanted to check and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.
 

Regards,

Zoe

[dtbrown81]

Hi Zoe,

I guess I'm still a little confused. I don't have HVAC, so I don't have an HVAC board. The other end of my thermostat wires go to the zone valves and the switch on the side of the furnace (which I assume powers the circulating pump, etc). Those are the pictures I posted previously. My furnace is natural gas/hot water heat. 

Thanks,

Dave

[zoeuvre]

Hello there, 

Thanks for getting back to us, and I'm sorry for the late response. Could you instead send us a photo of how your thermostat wires are connected to your current thermostat?

Keep us posted. We're happy to help.

Best regards,

Zoe

[dtbrown81]

Hi Zoe,

We are currently out of town for a few weeks, but I will be happy to do so when I return.

Thanks,

Dave

[zoeuvre]

Hi there, 

Alright! You can take note of the following steps above so that you can perform it as you visit the location where the thermostat is. Also, I'll keep this thread open but please be advised that as Community Specialists, we occasionally do a bit of housekeeping to keep the conversations in our community fresh and relevant. This includes locking threads after a period of inactivity. 

Thanks,

Zoe

[zoeuvre]

Hello dtbrown81, 

I wanted to check and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.
 

Regards,

Zoe

[dtbrown81]

Not at the moment as I will not be home until July 5.

I make a new post once I have picture of my thermostat wires.

Thanks,

Dave

[zoeuvre]

Hi Dave, 

Sounds like a plan! In the meantime, I'll go ahead and lock this thread within 24 hours. If you come across other information you'd like to pass along or have further questions, feel free to create a new post along with your thermostat's wiring setup. 
 

All the best,

Zoe