Honeywell Chronotherm III (furnace only/no AC) Wiring

[wanhanii]

I bought a Google Nest Learning Thermostat to replace a 30 year old Honeywell Chronotherm III - who should I contact to get help - an electrician or a furnace service person? Please advise, I'm trying to get this replaced. Thank you

[Patrick_Caezza]

Post a picture of the current thermostat's wiring.

Those are usually simple to replace with a Nest.

[wanhanii]

Honeywell Chronotherm IIIfurnacewire from thermostat

[Patrick_Caezza]

Interesting, Never seen a thermostat that has two of each wire connected to the terminals. It looks like they ran two cables in parallel from the furnace to the thermostat which makes no sense to me.

Do you have just one thermostat?

Do the thermostat cable only have 3 wires each?

[wanhanii]

only one thermostat - the cables have 5 wires each - you can see in the picture yellow and black are twisted out - only R, G and W are used

[Markjosephp]

Hello folks,

I wanted to ensure that everything was covered here.

Thanks for the input, @Patrick_Caezza.

I'm sorry for the late reply, wanhanii. I'd suggest contacting an HVAC technician for your Nest Thermostat installation. Incorrect wiring could cause an HVAC issue. With this, we can assure the use of the double wires connected to your existing thermostat.

If you have more questions, let us know so we can assist you right away.

Regards,

Mark

[Jake]

Hey there,

I wanted to check in and see if you managed to see Mark's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

[wanhanii]

Yes, thank you I did see his post. I am currently looking for an electrician or trained heating tech to look at my thermostat setup and try to install the Nest I bought last year. Thank you for following up.

[Markjosephp]

Hi wanhanii,

It's me again. I appreciate your effort in reaching out to an HVAC technician. But I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Regards,
Mark

[Markjosephp]

Hello there,

I'm checking back in — how's it going? Still need our help?

Thanks,

Mark

[wanhanii]

Hi - I am going to contact a local electrician to get it installed. I should be good to go after that. Thank you

[Markjosephp]

Hello wanhanii,

Sounds like a plan! I appreciate your effort. If there’s anything else I can help you with, please let me know.

Regards,

Mark

[Jake]

Hey there,

I am glad to hear you are getting an electrician to come out. With that being the case, I am going to go ahead and lock the thread at this time. If you do have any trouble once everything is set up, please feel free to create a new post.

Best regards,

Jake