topic Re: Can someone help me to place wires correctly? in Nest Thermostats

Can someone help me to place wires correctly?

Masha1 — Fri, 04 Mar 2022 04:41:19 GMT

I have rooftop AC TRANE PACKAGE HEAT PUMP Model# 4WHC3030A1000AA SERIAL#14495JGB3H

Top picture is my old wiring, bottom is Nest. I don't want to blow a fuse since I can't figure where brown and blue wires should go. As you can see the old thermostat didn't even use brown wire and Blue was in O.

Thanks

Re: Can someone help me to place wires correctly?

Patrick_Caezza — Fri, 04 Mar 2022 05:35:21 GMT

Just tape the Brown wire off if it wasn't used on the original thermostat.

The Blue wire should go to the */OB terminal on the Nest.

Re: Can someone help me to place wires correctly?

Masha1 — Fri, 04 Mar 2022 06:55:56 GMT

I did that and it cools however it only works for a few minutes then shuts off and the message in thermostat is "delayed" does it mean I need a C wire? Can brown wire be a C wire?

Re: Can someone help me to place wires correctly?

dhx227 — Fri, 04 Mar 2022 23:50:16 GMT

Yes, you need a C wire to power the Nest. However, you won't know if the brown wire actually is a C wire without either going to look at where it is connected at the furnace, or testing it with a voltmeter.

It's pretty simple stuff, but pretty hard to describe the possibilities since we don't know exactly how the installer may have wired it. The simplest might be to attach some pictures of how the thermostat wires are connected inside your furnace.
Orange or Brown are often used to control the direction of a heat pump. In your case, it seems like the installer chose the Blue wire.

Blue or Black are often used for the (C)ommon wire. Perhaps the installer felt Brown was closer to Black so used that? And Blue meant Cool... maybe...

There should be a wiring block that the thermostat wires are all connected to inside the heat pump (you will probably have to remove a cover). The wiring block will have similar letter codes.

Re: Can someone help me to place wires correctly?

Ryan_G — Sat, 12 Mar 2022 21:50:47 GMT

Hey folks,

I just wanted to follow up and see if you're still in need of help? Please let me know, as I would be happy to answer any questions you may have.

Thanks for all your help here, dhx227 and Patrick_Caezza.

Best regards,

Ryan

Re: Can someone help me to place wires correctly?

Ryan_G — Tue, 15 Mar 2022 23:32:10 GMT

Hey there,

Just wanted to jump in here to check to make sure that you saw our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Have a great day.

Best regards,

Ryan

Re: Can someone help me to place wires correctly?

Masha1 — Tue, 15 Mar 2022 23:48:19 GMT

Hi my AC is on the roof so I can't see which wire is what, so I probably have to hire a specialist. My thermostat works but I might have to get a C wire because it shuts off, also it only works either on cooling or heating but not both. I don't know what brown wire is dor, it was not plugged in old thermostat. I put blue wire in OB and it only blows cold

Re: Can someone help me to place wires correctly?

Ryan_G — Fri, 18 Mar 2022 12:24:13 GMT

Hi Masha1,

Thanks for your response and for providing more details about your system.

Based on your system descriptions, it would be best to get in touch with your local HVAC technician or check out Nest Pro installer partners for more help.

Best regards,

Ryan

Re: Can someone help me to place wires correctly?

Ryan_G — Tue, 24 May 2022 22:56:41 GMT

Hey folks,

Thanks for visiting the Google Nest Community.

Since this thread hasn't had activity in a while, we're going to close it to keep content fresh.

If you have additional questions, feel free to submit another post and provide as many details as possible so that others can lend a hand.

Hope this helps!

Kind regards,

Ryan