Nest Thermostat Not Cooling

Ask your electrical related questions here
Post Reply
aetedford
Posts: 4
Joined: Mon May 07, 2018 12:06 pm

Nest Thermostat Not Cooling

Post by aetedford » Mon May 07, 2018 12:08 pm

First warm weather using my nest thermostat and now trying to use the central air. However, only the fan turns on and it doesn't actually cool no matter how long I run it. (It worked perfectly in the winter with this setup)

Looking at the furnace and NEST, the wiring is as follows:

FURNACE --> NEST

R --> RH

W --> W

Y --> Y1

G --> G

C --> C


On the Nest, the remaining spots that do not have wires are: Y2, OB, RC, W2 aux, and *

Any help is appreciated.
Thank you.


User avatar
Admin
Site Admin
Posts: 518
Joined: Tue Nov 15, 2011 9:55 pm
Location: Canada
Contact:

Re: Nest Thermostat Not Cooling

Post by Admin » Mon May 07, 2018 1:24 pm

Is the circuit breaker and disconnect for the A/C unit turned on / connected? By fan you mean the house fan and not the fan on the A/C unit itself?

aetedford
Posts: 4
Joined: Mon May 07, 2018 12:06 pm

Re: Nest Thermostat Not Cooling

Post by aetedford » Mon May 07, 2018 1:36 pm

Yes, the house fan, not the a/c unit. When the nest states that it is cooling, I go outside and it is not on, at all.

Regarding the circuit breaker, great question. I am going to assume it is on. But, when I get home, I will check it out.

Thank you

User avatar
Aaron
Posts: 2502
Joined: Sat Jan 03, 2015 4:03 pm
Location: St. Paul, MN

Re: Nest Thermostat Not Cooling

Post by Aaron » Mon May 07, 2018 3:40 pm

Yeah you might have turned it off last Fall and forgot you did. I've done that before (forgetting I turned off the breaker) and wondered why it wasn't working. Now I just leave it on year around. Lol

Check your outside condenser's breaker/fuse box too. Sometimes they have little lamps indicating the presence of power, but in my box they are actually burnt out so if they aren't lit don't assume you don't have power.

User avatar
Admin
Site Admin
Posts: 518
Joined: Tue Nov 15, 2011 9:55 pm
Location: Canada
Contact:

Re: Nest Thermostat Not Cooling

Post by Admin » Mon May 07, 2018 7:23 pm

There is a disconnect switch near the A/C unit outside, remove, inspect, and reinstall the plug on it too. Well, that's required in Canada, I don't know where you are.

User avatar
Aaron
Posts: 2502
Joined: Sat Jan 03, 2015 4:03 pm
Location: St. Paul, MN

Re: Nest Thermostat Not Cooling

Post by Aaron » Mon May 07, 2018 7:58 pm

It is here in the US too. A lot of them are this handle module thing you have to pull out, turn it 180 degrees, and plug back in.

I've stopped messing with both the disconnect and the main breaker and just leave both on/connected year around. Because I kept forgetting over the winter whether I disconnected one, the other, or both... And I even forgot how to deal with that pull-out handle thing during the first sweltering day we had. I pulled it out but forgot you had to rotate it. I replaced the fuses and it still didn't work, and I finally remembered to rotate it. I swore I would never screw around with it again after that.

diggler306
Posts: 55
Joined: Wed Oct 15, 2014 12:53 pm
Location: Saskatoon

Re: Nest Thermostat Not Cooling

Post by diggler306 » Mon May 07, 2018 10:30 pm

So this is the first spring/summer that you've used the Nest? ie. You're questioning whether you wired the Nest correctly for AC?

It could be something else unrelated, like a bad capacitor in the condenser unit. I was about to post here on the forum because I'm having the same problem (turned Nest to cool, but condenser does not start up, and furnace fan only blowing normal air). Food for thought.

aetedford
Posts: 4
Joined: Mon May 07, 2018 12:06 pm

Re: Nest Thermostat Not Cooling

Post by aetedford » Tue May 08, 2018 11:05 am

Purchased the house last fall and then purchased the Nest. Never used the A/C. Now, finally starting to get warm and it's not working.

Looking at some of the comments, I should try to rotate the pull-out handle outside. Checked the circuit breakers. THey are all on.

User avatar
Aaron
Posts: 2502
Joined: Sat Jan 03, 2015 4:03 pm
Location: St. Paul, MN

Re: Nest Thermostat Not Cooling

Post by Aaron » Tue May 08, 2018 2:28 pm

Go ahead and check that. If you're still having trouble go ahead and jump in to this neighboring thread in the forum, another guy is having the same trouble as you (Nest not starting his AC):

viewtopic.php?t=6643

diggler306
Posts: 55
Joined: Wed Oct 15, 2014 12:53 pm
Location: Saskatoon

Re: Nest Thermostat Not Cooling

Post by diggler306 » Mon May 14, 2018 10:00 am

aetedford wrote:
Tue May 08, 2018 11:05 am
Purchased the house last fall and then purchased the Nest. Never used the A/C. Now, finally starting to get warm and it's not working.

Looking at some of the comments, I should try to rotate the pull-out handle outside. Checked the circuit breakers. THey are all on.
So the reason for my recent AC problems (condenser/fan would not turn on when Nest calling for cooling) was the high pressure switch had tripped inside the condenser unit. On my Lennox 13ACX there was a small panel you can take off and a red button to press to reset the switch. After I reset the switch, my unit was now getting the 24V signal from the thermostat to engage the contactor and fire up the unit.

It too me quite a bit of testing to isolate the issue, but check out my thread to see if it helps at all.

User avatar
emtnut
Posts: 1316
Joined: Mon Mar 02, 2015 7:21 am
Location: Canada
Contact:

Re: Nest Thermostat Not Cooling

Post by emtnut » Mon May 14, 2018 1:06 pm

aetedford wrote:
Tue May 08, 2018 11:05 am
Purchased the house last fall and then purchased the Nest. Never used the A/C. Now, finally starting to get warm and it's not working.

Looking at some of the comments, I should try to rotate the pull-out handle outside. Checked the circuit breakers. THey are all on.
I'd guess that you got this going already

If you haven't let us know. If it wasn't the outside disconnect, it's probably because R is tied to RH, and you need to jumper to RC as well.

Let us know if you need help :)
~~ This space for rent ... apply within :mrgreen: ~~

aetedford
Posts: 4
Joined: Mon May 07, 2018 12:06 pm

Re: Nest Thermostat Not Cooling

Post by aetedford » Wed May 16, 2018 6:53 am

Had someone come look at it last night. It was the capacitor on the unit. (Said that the top was bulged meaning it was bad) He replaced it, works like a charm! $100. I was convinced the whole thing was going to need replacing!

User avatar
Aaron
Posts: 2502
Joined: Sat Jan 03, 2015 4:03 pm
Location: St. Paul, MN

Re: Nest Thermostat Not Cooling

Post by Aaron » Wed May 16, 2018 8:06 am

It's always nice to positively identify a faulty part in the troubleshooting process. Hopefully that nailed it for you.

The worst troubleshooting is intermittent problems, and replacing parts on suspicion.

Post Reply