topic Re: Nest 3rd Gen Thermostat, heats when in cool in Nest Thermostats

Nest 3rd Gen Thermostat, heats when in cool

Bbradleybales — Sun, 17 Apr 2022 21:59:16 GMT

I installed a new nest 3rd gen learning thermostat. Wiring was all done correctly. However, when set in cool it heats. I confirmed the wiring configure for old Honeywell thermostat and the cooling wires for it were connected to cooling for nest. I uninstalled the nest and put back the Honeywell. It is cooling. Same cooling wires that were going to Y1, Y2, and G on nest. I don’t know why the nest was running heat??

Re: Nest 3rd Gen Thermostat, heats when in cool

Patrick_Caezza — Mon, 18 Apr 2022 01:31:28 GMT

Post a picture of the original thermostats wiring here.

Try this if you have a heat pump.

On your thermostat, go to Settings .
Select Equipment.
Select Continue > Continue.
Select Heat Pump.
The Nest Thermostat defaults to an O setting for heat
pumps.
- If the O option is highlighted, select B.
- If the B option is highlighted, select O.
Test your heating and cooling again to make sure the issue is resolved.

Re: Nest 3rd Gen Thermostat, heats when in cool

Bbradleybales — Mon, 18 Apr 2022 12:39:50 GMT

On the new Nest thermostat I had Y1 yellow, Y2 black, G green, Rc red, W1 orange, W2 white, and C blue.

I am attempting to attach a photo of old wiring from my phone, but not getting it to work.

Re: Nest 3rd Gen Thermostat, heats when in cool

Bbradleybales — Mon, 18 Apr 2022 12:40:53 GMT

Re: Nest 3rd Gen Thermostat, heats when in cool

stevenwhite8484 — Mon, 18 Apr 2022 13:49:21 GMT

if you have a heat pump the orange needs to land on the O/B if its still heating when in cool then the thermostat isnt communicating with the orange wire telling the reversing valve in the heat pump to switch to cooling mode. You can bypass this however and manually make the unit switch but you would have to be a little handy to do this. unfortunately a new thermostat might be required to permanantly fix the issue

Re: Nest 3rd Gen Thermostat, heats when in cool

Bbradleybales — Mon, 18 Apr 2022 15:24:54 GMT

Got it. So, it does turn out that the unit is a heat pump. When looking at the wiring in the old thermostat, even though the wires come in from the top should I be reading them as the bottom labels? Red as Rc, Yellow as Y, Blue as C, Orange as O/B, Green as G, White as Aux, and Black as E?

Re: Nest 3rd Gen Thermostat, heats when in cool

stevenwhite8484 — Mon, 18 Apr 2022 16:01:41 GMT

correct ive replaced a few of those thermostats for the reason you are claiming actually in my own home haha i had to jump the reversing valve until i got a new one.

Re: Nest 3rd Gen Thermostat, heats when in cool

Patrick_Caezza — Tue, 19 Apr 2022 00:33:11 GMT

Give this wiring a try

Black - E to * (set as emergency heat)

White - W2 to W2 (set as AUX heat)

Green - G to G

Orange - O/B to OB

Blue - C to C

Yellow - Y to Y1

Red - Rc to Rc (jumper to R not needed))

Re: Nest 3rd Gen Thermostat, heats when in cool

Bbradleybales — Wed, 20 Apr 2022 17:13:51 GMT

Thank you for all of your help. I have installed both Google Nest thermostats and they are both working perfectly.

Couldn't have done it without your help. Thank you again!

Re: Nest 3rd Gen Thermostat, heats when in cool

MelbaDT — Thu, 28 Apr 2022 06:29:52 GMT

Hey folks,

Thanks for answering, Patrick_Caezza.

Bbradleybales, glad to hear that you've managed to sort it out with the help of Patrick's suggestion above ― hat's off to both of you!

Feel free to let us know if you still have some questions in mind.

Best,

Melba

Re: Nest 3rd Gen Thermostat, heats when in cool

MelbaDT — Tue, 03 May 2022 04:56:43 GMT

Hi,

I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best,

Melba