honeywell TH2210DV Compatibily check

[tdcs]

Hi, the Nest Thermostat is compatible with my AC System? It's a honeywell TH2210DV

[sporfrog]

It looks like it is primarily an AC (cooling) system.  However I am curious...is there heating as well?  Maybe supplemental or emergency light-use heating?  I ask because the white wire is connected to AUX/E which, according to the manual, is "Aux/E  Auxiliary heat relay"

Also the system does not have a C "Common" wire.  While not always required it is best to have one, or at least plan for it should your system require it with a Nest Thermostat. Options

• Try without. In many situations it will work fine.
• Check to see if there is another wire such as black or blue unused and purpose it for C.
• Run new thermostat cable with more wires.
• Use the Nest Power Connector

You might also find the Compatibility Checker helpful.

[tdcs]

Hi @sporfrog , yes, it has heating as well, at least I guess it has, I'm Florida.

There is another wire hidden, a blue, can I use this one for C?

I tried already the Compatibility Center, and it sent me here lol

So can I buy a nest and it will work properly?

[sporfrog · Accepted solution]

Based on what you have written, and the Honeywell manual, the white wire is almost certainly heat and probably can be connected to a W or W1 terminal on a Nest thermostat.  I have to admit that I am not familiar with a thermostat that uses Aux/E for heat, but I am fairly confident white to W would work on a Nest.   Red, White, Yellow and  Green are very common wires for a simple Heating and Cooling System.

Regarding the blue wire, if you have the ability, open the HVAC unit to see if blue is connected to a C or Common terminal.  If so, yes you can use it for Common and that would be the best solution.

If you happen to have a multi meter you can also test blue to R for 24V to see if blue is connected to C and the HVAC unit. 

[tdcs]

Hi, @sporfrog I made the installation and used the blue wire as C, and worked great, I had some issues with the Nest identifying the G wire, so the fan was not working, after reviewing the installation and it was all fine, I added the new wire in the Home app and started to work. Thanks!

[sporfrog]

Glad it is working!

[EdwardT]

Hi folks,

@sporfrog, thanks for the help!

@tdcs, I'm glad to hear that everything is working fine now. Please observe it for now and let us know if anything comes up.

Thanks,

Edward

[EdwardT]

Hi tdcs, 

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[tdcs]

Hi @EdwardT , all good here, thanks

[EdwardT]

Hi tdcs,

Thanks for confirming. I will be locking this thread now. Please feel free to create a new thread should you have some more questions or concerns in the near future and we'll be more than glad to help.

Thanks,

Edward