topic Re: Wiring neat thermostat in Nest Thermostats

Wiring neat thermostat

RAYLENNON — Thu, 05 Jan 2023 03:30:07 GMT

can anyone offer any help replacing my old thermostat with Nest. Not sure which wires should be installed where in Nest. Thanks.

Re: Wiring neat thermostat

Houptee — Thu, 05 Jan 2023 04:06:18 GMT

What kind of heating system do you have?

It looks like a AC system (RC power wire is usually for the cooling system)

I see a separate Heating system (R wire is usually for heat only system) and black wire going to W (heat signal wire).

So I think you have two separate systems one is your AC and a separate heating system possibly a boiler with radiators?

Can you confirm if this is what you have.

If I am correct then you have a dual transformer system (Each system has its own 24v power transformer).

The Nest (non learning model) will not work with a dual transformer system.

Only the Nest Learning model can work this kind of system with dual transformers.

Re: Wiring neat thermostat

RAYLENNON — Thu, 05 Jan 2023 15:18:38 GMT

That’s correct it’s dual system. With baseboard heat.

Re: Wiring neat thermostat

RAYLENNON — Thu, 05 Jan 2023 15:29:45 GMT

this is the thermostat we have. Disregard wiring, this is the neighbors T-stat

Re: Wiring neat thermostat

Houptee — Thu, 05 Jan 2023 15:42:46 GMT

That model is not designed for 2 R wires like you have.

You can get a Nest Learning model it has RH and RC inputs.

Or if you are handy and want to do a little wiring you can make the regular Nest work if you get a relay and put it near the boiler.

With a relay the power R will be coming to the Nest from the AC system, and when it wants heat it sends 24v out W wire to the relay which clicks on like a switch and turns on the boiler. This relay separates the two systems transformers but allows the Nest to control the boiler.

So those are your options, Get Nest Learning or buy a relay and do a bit of wiring (not that hard).

The relay is under $20.

https://www.amazon.com/dp/B004XS148C

Re: Wiring neat thermostat

RAYLENNON — Thu, 05 Jan 2023 15:53:37 GMT

Ok thank you. And if I change the thermostat, where do my wires plug into?

Re: Wiring neat thermostat

Houptee — Fri, 06 Jan 2023 16:29:06 GMT

The thicker wires are the AC system

Put Red to RC

White to Y1

Green to G

The thinner wires are the boiler

Put thin Red to RH

thin Black to W1

The only other issue is if you do not get good power readings after install you might need to add a C wire coming from the AC system but you can try it without the C wire and do a Power Test to confirm you are getting good Vin voltage and enough current Lin.

After you install watch this video to understand the power readings you need to look for without a C wire.

https://youtu.be/GHkfnRp6Tj8

Re: Wiring neat thermostat

aatienza — Mon, 09 Jan 2023 23:59:45 GMT

Hey there,

RAYLENNON, checking in — we hope you've got the answer you're looking for. Let us know if you have more questions in mind.

I appreciate the help here, Houptee.

Thanks,

Archie

Re: Wiring neat thermostat

aatienza — Fri, 13 Jan 2023 06:38:59 GMT

Hey there,

I just wanted to follow up to see if you still need our help. Please let us know as we would be happy to answer any questions you may have.

Thanks,

Archie

Re: Wiring neat thermostat

aatienza — Wed, 18 Jan 2023 06:42:24 GMT

Hello there,

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.

Thanks,

Archie