topic Re: Nest thermostat heats when it’s supposed to cool. in Nest Thermostats

Nest thermostat heats when it’s supposed to cool.

ArashS — Thu, 08 Jun 2023 20:51:45 GMT

Hello everybody,
It's been couple of weeks dealing with this issue, hope getting some helps from you guys.
I have a HP system which is working absolutely fine with the old thermostat (So I don't think reversing valve has any issue). If I install Nest Learning thermostat G3, I get hot air from vents while it is set to cooling.

Changing orientation didn't help.

I believe wires are connected correctly. Y1, G, O/B, W1, C and Rh are connected.

Troubleshooting returns T02 error (single stage cooling problem).

Many thanks,

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 01:34:03 GMT

@ArashS , please post the picture of your old thermostat showing the wires attached before you started disconnecting them. All heat pumps are manufactured in of two default modes. The O models and the B models. O models default to cooling and B models default to Heating. Most heat pumps are O models. The original concept was that the models would typically be sold in the north where they need to eat more than I need cooling, and all models will be sold in the south where they need cooling a lot more than I need heating. By default the nest thermostat when it finds a heat pump configuration, will ask you what type it is, and if you do not know, it will simply default to an 00 and then, when you run the system test, you will know if you need to change.

On your thermostat go to SETTINGS > EQUIPMENT > CONTINUE > CONTINUE > HEAT PUMP. As I said, there will probably be a checkmark in front of O. No matter which one has the check mark in front of O or in front of B, simply change it to the other one, now choose DONE.
Give your system a cooling test and see if it’s cooling again.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 02:44:50 GMT

Thank you for replying to this post. Here are photos:

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 02:45:49 GMT

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 04:30:21 GMT

@ArashS for a heat pump like you have, the white wire must be placed in W2/Aux. After that put the display back on and choose SETTINGS > EQUIPMENT > at this point you will see the backplate and the wires detected by the Nest. Select CONTINUE and CONTINUE and then HEAT PUMP. Here you will see the O and B and one has checkmark ✔️ in front of it. Just select the other one and press the display and move the checkmark ✔️. So if the checkmark is on O, move it to B, if it is on B, move it to O.

Now select DONE. And test your cooling. You should have cold air now.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 17:01:22 GMT

White wire is placed in W2 now. Changing orientation doesn't make any difference. I have tried it many times. I think there is something wrong with the base. Do you think that is possible?

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 18:16:21 GMT

@ArashS, let’s go ahead and place your thermostat into the pro set up mode. On the nest display Goto SETTINGS > EQUIPMENT > CONTINUE > CONTINUE > PRO SETUP > CONTINUE. At this point you will see the nest backplate show which wires are attached. The wedges will be green if OK and Yellow if it needs defined. Rotate the ring to any yellow wedge. Select and define it function. Go check and tell what wedges are Yellow. You have wires in Rc, Y1, G, OB, W2, and C.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 19:54:12 GMT

I checked yellow ones, now they are all green and defined.

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 19:55:16 GMT

Still blowing hot air.

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 20:50:36 GMT

@ArashS , One of the things we recommend for heat pumps is to put the R wire in Rc. In the picture you originally posted the red wire was in Rc. Why was it changed to Rh? I would like to confirm that you changed the Heat Pump Equipment type from O to B or B to O. And saved the Change. If the mode is backwards, and you put the system on Heat, the heat mode will blow cold air. If you get heat on both you likely have a problem with your reversing valve.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 21:35:14 GMT

Connecting the red wire to Rc or Rh doesn't fix the issue, I have tried many times. Changing orientation from O to B or B to O doesn't make any difference. HVAC system blows hot air always no matter Cooling is activated or Heating. I think Nest doesn't change the orientaion at all. As I mentioned on my first post, If I connect the old Emerson thermostat, heating and cooling are working fine, so it's not abot reversing valve.

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 21:48:13 GMT

Do you have a metal paper clip handy? Turn the breaker to the air handler off. Then remove the Red wire, Orange wire, yellow wire and green wire from the Nest backplate. Hook those four wires together with a metal paper clip. Turn the power back on do you get cool air or hot air? Turn power back off. Remove the orange wire leaving the Red, Yellow, Green wire in the paper clip. Wait 5 minutes then turn the power back on. Do you get cool air?

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 22:26:27 GMT

I just tried.
Red+Orange+Yellow+Green => Cool air

Red+Yellow+Green => Hot air

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 22:35:11 GMT

@ArashS , ok sometimes we find that the customer did not fully insert the wires into the nest backplate. When a wire is fort inserted, the first contact point is used to detect a wire is inserted, then you push the wire farther in to reach the control contact point. Note the pictures below showing a Common wire inserted just enough to signal it is inserted yet not far enough to reach the control contact.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Fri, 09 Jun 2023 22:58:33 GMT

I just stripped orange wire more and pushed. Unfortunately, still the same. Hot air in cooling mode.

Re: Nest thermostat heats when it’s supposed to cool.

CoolingWizard — Fri, 09 Jun 2023 23:55:18 GMT

Ok @ArashS , You need to request a product warranty replacement of the entire unit. I’m so sorry that this is happened to you and hope you the best.

AC Cooling Wizard

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Sat, 10 Jun 2023 01:59:39 GMT

Thanks a lot for your time and support. I'll get another one.

Re: Nest thermostat heats when it’s supposed to cool.

Markjosephp — Tue, 13 Jun 2023 21:34:01 GMT

Hello folks,

I wanted to ensure that everything was covered here.

Thanks for looking into this, @CoolingWizard.

@ArashS, I hope you've found the answer you're looking for. How's it going? Have you had a chance to contact your installer, or at least our support team? If you're still in need of assistance, feel free to let us know.

Regards,

Mark

Re: Nest thermostat heats when it’s supposed to cool.

ArashS — Wed, 14 Jun 2023 13:13:18 GMT

Yeah, thank you for the follow up!

Re: Nest thermostat heats when it’s supposed to cool.

Markjosephp — Wed, 14 Jun 2023 20:02:08 GMT

Hi ArashS,

I'm glad to hear it was sorted out! It looks like we can consider this one complete, so I will lock the thread within 24 hours unless I can help out with anything else.

Regards,

Mark