AC not cooling after Nest install

[Nat4]

Hello, 

We recently updated our old thermostat with a Nest over the winter. We had no issues with the heat function in the colder months (we live in MN) but now that we need to switch to AC, it doesn’t seem to be cooling our house down. Background: our house is less than a year old, and there were no issues running ac last summer. I followed the wiring instructions as provided by Google when I set the nest up. The AC unit sounds like it’s running when you turn the AC on via the nest and air blows but it doesn’t get cold. 

is this a nest connection issue? Or an AC unit issue? Thanks in advance for any help! 

[CoolingWizard]

@Nat4 , We need a little more information to help you best. Can you post the pictures of the old thermostat wiring and the nest backplate showing the wires?

Do you have a Heat Pump or a Gas Furnace? 

AC Cooling Wizard

[Nat4]

Hi there! Appreciate your help. Here are pictures of the old and new wiring. We have a gas furnace. 

  

[zoeuvre]

Hello Nat4, 

As you’ve requested, I'm going to lock this thread and mark it as complete. Feel free to create a new one if you have more questions or have other concerns in the future.
 

All thanks for your help, @CoolingWizard. 

Cheers,

Zoe

[Misw1]

Any help with this. I’m having the same issue 

[Nat4]

None yet but hoping there’s a knowledgeable pro out there 🙂 

[CoolingWizard]

@Nat4 @Misw1 
We have seen a number of problems when the system is not a heating only system picture when you have a combination heating and air-conditioning. We recommend that you put the red wire over to RC and Not RH. I’m not sure why that works or why that should make a difference, but for some reason the software does this. 

AC Cooling Wizard

[Nat4]

Hi there, 

Thanks so much! I switched the wires are 45 min ago but still no cool air/dropping temps. I’ll give it a bit longer to see if theres any luck! 

[Nat4]

Unfortunately that didn’t seem to do the trick. 😞 air comes out but not cold air so the house remains at 75 (or warmer). I see this under pro set up 

[CoolingWizard]

If the the thermostat does not present an E type error, the non cooling problem is more than likely your HVAC system.  When R is connected to Y, the air conditioner is turned on.   Why might an HVAC system not be cooling?

Check your outdoor unit, Is the Fan spinning and the compressor running?
Is there any signs of a refrigerant leak? This will be an oily stain somewhere.  
If you have access to the air handler, the 3/8” copper pipe should be hot to the touch and the larger pipe inside the insulation should be cool.  

AC Cooling Wizard

[Nat4]

Hi! I had an AC pro come out to take a look, unfortunately had a hard time understanding the issue but it seems to have something to do with the pressure of my unit. It was installed in winter which impacted the pressure. I kept my nest wired as suggested and with the work the AC pro did, I’m back up and running. Hoping to have another pro out to ensure the issue was fixed and won’t continue but wanted to close the loop here. Thank you for all your help!