topic Re: 2-wire Honeywell (W & B) to nest thermostat in Nest Thermostats

2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sat, 15 Apr 2023 16:01:21 GMT

Hi,

I have old Honeywell chronotherm 2 thermostat (Honeywell-Chronotherm-II-manual)

but it’s just two wires (label W and B)

My gas furnace (heating only) is Payne PG8MAA purchased 2010 (Payne-Pg8maa-manual )

I was told there may be an equipment interface module (EIM) installed between the furnace and the thermostat. I donno where that is or whether that is true. If that’s true, I need a licensed electrician to remove that in order to replace my old thermostat with those new thermostat like nest. That would be more expensive that I thought. Any advise?

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sat, 15 Apr 2023 16:03:55 GMT

This is the Honeywell chronotherm II thermostat with 2-

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sat, 15 Apr 2023 23:16:52 GMT

Correction: the thermostat model is chronotherm III ( Honeywell-Chronotherm-III manual )

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sun, 16 Apr 2023 20:14:00 GMT

The Payne manual online has the wiring diagrams on page 23. The bottom one shows W,C,R, G, Y wire labels, and there is NO wire label B. W,C,R would be connected between the furnace (heat only) and thermostat. So the red wire on my thermostat could be misplaced and should have been connected to label R on the thermostat.

Re: 2-wire Honeywell (W & B) to nest thermostat

zoeuvre — Thu, 20 Apr 2023 19:08:26 GMT

Hi wilsong,

Thanks for posting here in Community forum, and I'm sorry for the delayed response. I'd love to know more about this.

Please send us a photo of your actual furnace control board where the other end of the wires are connected so I can further determine its compatibility with our Nest Thermostats.

I'll look foward to your response.

Best,

Zoe

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sun, 23 Apr 2023 00:57:13 GMT

Hi Zoe, thanks for your help! Here are some pictures of the furnace. Let me know if you need more information. Thanks!

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Sun, 23 Apr 2023 01:02:09 GMT

The first picture is not clear. Resend again .

Re: 2-wire Honeywell (W & B) to nest thermostat

zoeuvre — Tue, 25 Apr 2023 16:40:53 GMT

Hi there,

Thanks for getting back to us. Your Honeywell Chronotherm thermostat has the non standard labels that we have on our Nest Thermostat though your Payne PG8MAA gas furnace control panel follows it otherwise. In this case, it appears that your system is wired to your thermostat in a proprietary way.

Proprietary systems aren’t compatible with Google Nest Thermostats. However, some proprietary systems can be rewired by a pro installer to be compatible.

Let us know if that helps.

Thanks,

Zoe.

Re: 2-wire Honeywell (W & B) to nest thermostat

wilsonng — Wed, 26 Apr 2023 01:22:53 GMT

Thanks Zoe. I’m not clear. Could you elaborate what do you mean by non-standard labels?

Also, does that mean there is an equipment interface module (EIM) installed between the furnace and the thermostat? Is it installed behind the wall of the thermostat or underneath the crawl space ? Thanks.

Re: 2-wire Honeywell (W & B) to nest thermostat

zoeuvre — Sat, 29 Apr 2023 17:21:24 GMT

Hey wilsonng,

Thanks for getting back to us. Non-standard labels are labels that the Nest Thermostat doesn't have (for instance 1,2,3, or A, B, C). Have a look at this article and let us know if you need more help.

Also, if your Honeywell Chronotherm thermostat has the non standard labels and your Payne PG8MAA gas furnace control panel has, there should be an equipment interface module or relay behind the wall.

Regards,

Zoe

Re: 2-wire Honeywell (W & B) to nest thermostat

zoeuvre — Wed, 03 May 2023 20:06:50 GMT

Hey there,

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.

Thanks,

Zoe

Re: 2-wire Honeywell (W & B) to nest thermostat

zoeuvre — Thu, 04 May 2023 20:09:12 GMT

Hello wilsong,

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you run into any more issues in the future, please feel free to create a new thread.

Cheers,

Zoe