Nest thermostat sometimes turns on heat and AC at same time

[newcire]

Some times my furnace is turned on when the AC is running. Other times it'll just turn on the heat when I'm expecting AC. I don't get any errors on the wiring but i'm wondering if there is still an issue (see wiring below -  the blue wire is not being used)

 

[Aliciadawn]

Mine is doing the same this it will cool for a while then all of a sudden blow hot air. I have reset and don’t know what else to do with it. Was hoping you would have replies to ur post 🤷🏻‍♀️

[CoolingWizard]

@newcire can you post the picture you took of the thermostat wiring of your old thermostat please.  

AC Cooling Wizard

[newcire]

Hi CoolingWizard, attached is the old wiring. Please note that we added AC between switching to the Nest.

 

[Markjosephp]

Hello everyone,

I wanted to stop by and see how I could help.

Thanks for the help here, @CoolingWizard.

@newcire, it appears to be an incorrect wiring setup causing odd behavior on your HVAC. Could you confirm the wires between Y1 and W1 terminal from your HVAC system control board? Based on your old thermostat wiring, you have the black wire at the W terminal. Here's how you should wire your Nest Thermostat:

• Orange wire > Y1 terminal (Cooling)
• Green wire > G terminal (Fan)
• Blue wire > C terminal (24 V Common)
• Black wire > W1 terminal (Heating)
• Red wire > Rc/Rh terminal (Power)

@Aliciadawn, can you also share a photo of your old thermostat and the Nest Thermostat's wiring?

Please keep me posted.

Regards,

Mark

[Aliciadawn]

Here’s my wire set up…… 

 

[Aliciadawn]

The heat works perfectly in the winter the only problem is in the summer sometimes we get heat blowing instead of air…. Makes for a stuffy house

[Aliciadawn]

 

[CoolingWizard]

Ohm your on your app.  Sorry, my instructions were for the nest display. 

AC Cooling Wizard

[Aliciadawn]

I don’t have the old thermostat 🤦🏻‍♀️ I tossed it about a week after we set this one up🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️

[CoolingWizard]

@Aliciadawn , you wired your Nest Thermostat as a Heat Pump, the *OB wire is the change over valve. When you finished installing the Nest, did perform and system test for Heat and Cool? You have a wire in the W and that will be defined as auxiliary heat. With heat pump system the auxiliary heat is Electric Heat Strips in the air handler.  If you have say a gas furnace, you would be a Duel Fuel type of system. 

AC Cooling Wizard

[Aliciadawn]

Ok this is definitely over my head sorry but when my dad comes bye I’ll have him look at it. It’s is a heat pump the nest is connected to and when it was connected at first we did follow the directions to test it. 

[CoolingWizard]

@Aliciadawn , when you tested it, did the cooling work?  You run a test again by going it SETTINGS > EQUIPMENT > CONTINUE > TEST.  Run a cooling test and allow the test to run for 10 minutes. You should feel the air coming out very cool.  If it is hot, like the heater is on, we will need to investigate further.  Now, I know I can get you through this without anyone else being needed.  

AC Cooling Wizard

[Aliciadawn]

Wow thank you so much!!! I’ll run a test and get back to you

[Aliciadawn]

I swear I must have a knock off Nest or something when I goto settings on the nest it just gives me wiring or reset reboot options and the settings on my app isn’t any help either

[CoolingWizard]

@Aliciadawn , when you select SETTINGS, then you scroll to EQUIPMENT, does that work at all?

AC Cooling Wizard

[newcire]

Hmm now my AC just turns on and off in 20 second intervals

[newcire]

@Markjosephp what about the brown wire?

[newcire]

Nvm, figured it out. My ac is tied to the brown wire. Thanks @Markjosephp @and @CoolingWizard 

[CoolingWizard]

@newcire To verify your system, take the G wire, the R wire and the Y wire and hook them together.  Does the system continue to run? Also, Newcire, you need open your on message thread as this message thread is for Aliciadawn.  

AC Cooling Wizard

[Aliciadawn]

I put a pic under the wiring pic of the app on my phone settings….. there is nothing for equipment……. On the actual nest I do have equipment but it is just asking about wiring or resetting. Too bad ur not local!!! Haha