topic Need help with nest not working ac/ turns on heat in Nest Thermostats

Need help with nest not working ac/ turns on heat

Ericjay — Fri, 04 Mar 2022 21:18:12 GMT

Just got a nest thermostat set it up and I have two old thermostats. One for entire house and one thermostat that just controls upstairs. I installed nest in main downstairs here is the wiring

When I run ac it blows out heat not ac and it does it in my upstairs bedroom that is on its own thermostat. Here is the wiring on upstairs unit

here is my best unit I installed

here is my wires

any help would be appreciated. When I turn on heat on nest unit it turns on ac?? But this nest is controlling my upstairs unit I don’t no what to do please help!!!

Re: Need help with nest not working ac/ turns on heat

dhx227 — Fri, 04 Mar 2022 23:18:48 GMT

Did you follow the procedure laid out here: https://support.google.com/googlenest/answer/9249351?hl=en
IE, when you were configuring/setting up the Nest, did you identify what the wire was that you plugged into * O/B?
I can only make some assumptions based on your wiring and what you say is happening, but I have a pretty good guess. The Orange or Brown wire is often used in a heat pump system to indicate which direction the heat pump needs to operate in: heating or cooling. It sounds like the Nest did not get set up to correctly know this was controlling the heat pump changeover valve.
I've not had to reconfigure this, so I'm not sure if you need to just reset the Nest settings and configure it again, or perhaps just unplug the O/B wire and then plug it back in so the Nest senses that it's there and then asks to configure it.

HTH!

Re: Need help with nest not working ac/ turns on heat

Patrick_Caezza — Sat, 05 Mar 2022 01:43:13 GMT

Do you have two separate units or just one with a zone controller?

Your wiring looks correct but you only posted a picture of one Nest, do you have a 2nd one?

Re: Need help with nest not working ac/ turns on heat

Ericjay — Sat, 05 Mar 2022 02:35:45 GMT

I have 1 ac unit. 2 thermostats main thermostat downstairs that I’ve replaced with a Nest the upstairs thermostat controls a one bedroom and I’ve left the thermostat alone. I have reset it three times checked all my wiring and I have everything correct. But when I have it on ac it blows in the upstairs zone heat not ac and when I put on heat it blows ac

Re: Need help with nest not working ac/ turns on heat

Ericjay — Sat, 05 Mar 2022 02:40:24 GMT

this is the current unit that I replaced with nest but I have one upstairs that controls just one bedroom zone. I left the upstairs thermostat in place.

Re: Need help with nest not working ac/ turns on heat

Patrick_Caezza — Sat, 05 Mar 2022 03:10:33 GMT

Having one main unit and two thermostats means you should also have a zone controller. It should be located close to the air handler.

See if you can find and post a picture of it wiring, make, and model.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 21:46:11 GMT

I tried to hook up my old thermostat and now I have same issue. But one thing I forgot is that the upstairs thermostat had a jumper cable on it. I forgot to take a photo of the jumper cable before I uninstalled it. The jumper color was red but I don’t no where it went. So now I have no heat or air. I can take a photo of the unit but I’m not sure where it is. I have stuff in my garage I can send you a photo of that. I think my issue is that I took off the jumper cable and I should not have. The jumper cable red in color was in my upstairs thermostat.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 21:48:15 GMT

this is the unit upstairs that controls zone for one room upstairs that I have. I took off jumper cable and did not take photo and not sure where it went. Now when I turn on ac it blows heat out of wrong zone. So I have broke my entire house ac/heat.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 21:54:16 GMT

here is the photo you requested.

Re: Need help with nest not working ac/ turns on heat

dhx227 — Mon, 07 Mar 2022 22:19:38 GMT

The jumper would go between Rc and Rh. Basically, that is telling the thermostat that the power source for heating is the same as for cooling.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 22:39:48 GMT

Thank you I hooked it up jumper wire and I’m still having. Same issue. It will only put out heat and wrong zone. I think my unit is broken and needs freon. Older unit that take r22 I have not used it in a few months due to colder weather.

Re: Need help with nest not working ac/ turns on heat

dhx227 — Mon, 07 Mar 2022 22:42:25 GMT

Okay. Sorry to hear about that. There's only so much we can do over messages. Sounds like you should have a tech out to check everything and they should also be able to go over the wiring and help you setup up the Nest.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 23:10:30 GMT

I fixed it. Issue was I had a jumper wire on both my thermostats. Now it’s blowing cold ac. Thank god. Here is a photo of my main thermostat downstairs. Had white jumper from w2 to e. Once I hooked that up it works perfect.

now should I try to hook the new nest unit back up now that everything is working? Do I jump the white wire on the nest unit when I hook it up?

as you can see the white wire broke.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Mon, 07 Mar 2022 23:17:25 GMT

Awesome that worked. Ac blowing now

Re: Need help with nest not working ac/ turns on heat

dhx227 — Tue, 08 Mar 2022 01:14:03 GMT

E & L terminals are for activating the emergency heat relay and emergency heat lamp (which help get the heat pump up to operating temp in cold temps). That is really interesting that it is not working correctly unless the white wire has been jumpered to E.

AFAIK the Nest does not support emergency/auxiliary heat controls, though perhaps that can be configured by a Nest Pro on the Learning or -E models. Maybe @Patrick_Caezza can weigh in on that.

Re: Need help with nest not working ac/ turns on heat

dhx227 — Tue, 08 Mar 2022 01:15:11 GMT

You didn't by chance happen to bump the switch to Emergency mode did you?

Re: Need help with nest not working ac/ turns on heat

Patrick_Caezza — Tue, 08 Mar 2022 02:59:53 GMT

That picture is for a unit and not a zone controller I think.

A zone controller will look something like this.

Re: Need help with nest not working ac/ turns on heat

Ericjay — Tue, 08 Mar 2022 09:32:54 GMT

I have never seen one of them in my house. I hooked everything back up the way it was before I started my new best install and I have it working correctly. I then reset everything and attempted to install nest again and best works. But it blows heat when I have it in ac? So not sure what my issue is I am going to buy the new nest unit and see if that works I guess or stay with my old units. Any ideas?

Re: Need help with nest not working ac/ turns on heat

Ryan_G — Sat, 12 Mar 2022 21:49:09 GMT

Hey Ericjay,

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 your help, dhx227 and Patrick_Caezza.

Best regards,

Ryan

Re: Need help with nest not working ac/ turns on heat

Ryan_G — Tue, 15 Mar 2022 21:50:23 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