Air conditioner keeps running but not cooling.

[LilSnot]

We've been having issues with the air conditioning unit fan running but is not cooling the house. I power off the thermostat and the air conditioner and let it set for a while to reset it. When I turn it all back on again everything's working fine again. We had the air conditioning technician out and he went over the whole system. He stated The AC unit is in perfect condition but that Nest thermostats were having problems with low voltage issues.  Has anybody else heard anything about this and is there any solution?

[Ashepherdson]

Just want to confirm the actual condenser unit outside is turning on yet your home is not cooling at all?  If this were happening at my home I would check a few different things, being the refrigerant levels in the a/c system, as well as the lines for the a/c all the way to the air handler to see if there's anything frozen or leaking.  If the a/c condenser is turning on then your system should be blowing cold air.  

[RRuckus]

Yes, same issue. Just installed a new Google Nest Thermostat (the model using two AAA batteries) to replace an old Nest Thermostat. After install, the Google Nest Thermostat showed "Cooling - Starts in " and would show a countdown for a few minutes. At the end of the countdown, the fan would kick on but the condenser (AC unit) would not start and the thermostat would go back to "Starts in..." and the whole process would begin again. It finally started working normally after I left it alone for a few hours. Then, our HVAC technician came out to install a water safety switch on our furnace and had to turn the power off to do so. After turning the power back on, the thermostat is now doing the same useless cycling. I'm hoping it starts working again after a few hours but this is frustrating.

Our HVAC tech mentioned that he's seen this issue with other Google Nest thermostat installations. Everything I've read on the internet (caveat emptor) points toward a low power issue but this was not an issue with our previous thermostat. I have not found a solution except for hoping it will work after a while, but that's not good enough with summer on the doorstep. 

[LilSnot]

Thank you very much. That's exactly what my HVAC technician set. He said he sees that the Google nests do that. He mentioned something about low voltage issue

[Jeff]

Hey everyone,

Things slowed down here a bit, but I wanted to check in and see if anyone was still having an issue here. A couple of members have mentioned ensuring that the C-wire was being used. If you aren't using that wire, that would explain the low voltage problem. If you are using the wire and still see the issue, please let me know and we can look at more resolution steps for your setup.

Thanks,

Jeff

[Lcreyes]

How can I set up the C wire 

[Markjosephp]

Hello folks,

I'm sorry for the delayed response, and I wanted to stop by and see how I could help.

@CaroG, checking back in — how's it going? Still need our help?

@Pmw9554, I did find a helpful article with some steps to troubleshoot strange cooling or heating behavior. Please let me know if that helps, or if the issue still persists.

@Lcreyes, thanks for taking the time to post to this thread about the C wire installation. Here are some resources to assist you in installing a Nest Power Connector as a replacement for the common wire on your HVAC system that might help.

• Nest Power Connector installation article
• How to install the Nest Power Connector - video link

If you need help from a professional installer, you can schedule an appointment and get pricing from OnTech, our pro installation partner.

Please let us know if you need more help.

Best regards,

Mark

[Markjosephp]

Hi there,

I wanted to see if everyone still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

[Markjosephp]

Hello there,

I'm just checking in to make sure that you've seen my response. Please let us know if you have any additional questions or concerns before I lock this thread in 24 hours.

Best regards,

Mark

[Jeff]

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Jeff

[evac18]

I just replied to my earlier post but I wanted to note that my issue is similar to the initial post by lilsnot where it works most of the time (both the fan and condenser are normal) but then sometimes the condenser will stop working until you let it completely turn off then turn back on again. 

[evac18]

As noted below, I made sure the C-wire is connected

[Jeff]

Thanks for the added info, evac18. I'll need to dig a bit deeper on this. I appreciate the extra input and the willingness to work with me on this one.

Thanks,

Jeff

[Ryan_G]

Hey everyone,

I'd like to jump in here and check if you've seen Jeff's response. Let us know if you need more help by replying to this thread.

Thank you for your help, Jeff.

Regards,
Ryan 
 

[evac18]

I’m not sure if I missed something but Jeff just said he needs more time to look at it. Is there a solution you are referencing, Ryan

[Ryan_G]

Hey evac18,

Thanks for the reply.

Please bear with us as what Jeff has mentioned, he is into checking further details on this issue.

We'll keep you posted here in the thread.

Regards,

Ryan

[Ryan_G]

Hey there,

Thanks for being here in the Google Nest Community. 

I'd like to bump in here and make sure that you’ve seen our response.
Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Have a great day.

Best regards,
Ryan
 

[evac18]

Hi Ryan,

Are you just pasting this in without reading at all? The last post in this thread was you saying Jeff needs more time to look into this after. You did the same thing before:

Jeff: I'll look into this further

Ryan: Did you see Jeff's response? Is everyone good now?

Me: No, Jeff said he is still looking into it

Ryan: Please be patient, Jeff is looking into it

Ryan: Everyone good? I'm locking the thread.

[Patrick_Caezza]

Do you have a C wire installed?

• Nest thermostats are designed to work without a common ("C") wire in most homes. During installation, a small number of customers may find that the Nest Thermostat does not receive sufficient power. The Nest Power Connector or a C wire may be necessary. See g.co/nest/cwire for details.

[mikev552]

Is the "C" slot being used on the Nest? Low voltage means the internal battery is losing power and not able to charge. If your C-wire is not there then this is most likely your issue. 

[mikev552]

Its very important your C wire is connected. WIFI like a constant supply of power. This will supply power even when the AC/heat is off.

[evac18]

I think I'm having the same issue. This usually happens at night - it gets hot during the day and will take a couple of hours to cool down to the preferred temp at night. These nights, we wake up in the middle of the night or morning and the temperature is still a few degrees warmer off the setting and shows it was running the whole time. Turning it off for a while then turning it back on will get the cool air flowing again. When I switch from my gen 3 back to the Nest Thermostat E that my unit came with, it's working again. Were you able to fix this with the C wire like the other posts suggest or did you find another solution? Unfortunately, I can't make any changes right now to test myself.

[evac18]

I'm still having this issue. I switched back to my 3rd gen learning thermostat and made sure the C-Wire was connected this time. I am still having the same issue. Between my last post and now (over a month) the Nest thermostat E was working perfectly. I have been waking up in the morning and the fan has been running all night and the temperature is a few degrees off from the target temp. Again, it is fixed by just changing the temperature up to let it completely stop for a minute and then setting it lower again. I also have a sensor in the bedroom which is what it uses at night.

[CaroG]

I’m having this very same issue. I don’t have a C-wire and have had this problem a handful of times on the 2nd gGen and I’m usually able to fix the issue by popping off the base, charging and reattaching. However, 1 month ago the issue did not resolve so I purchased a brand new 3rd Gen and all I did was popped it into the the same base. It limped for a month in that it would take longer to cool and now it’s doing the same **bleep** thing! Although I appreciate the 24hr Live person support I don’t feel this should be an ongoing issue. Im still within the timeframe for a full-refund. Can someone recommend another smart thermostat? Thanks.

[Ryan_G]

Hi CaroG,

Thanks for reaching out here in the Google Nest Community.

This is one of the odd behaviors of an HVAC system without a C wire connected. You could check the unit and look for an unused wire and possibly we could connect it as a C wire. If you don't have a C wire, you may check this Nest Power Connector.

Regards,

Ryan

[Pmw9554]

Any resolution here?? I am having the same issue, working from home and it is hottt. Says cooling and it is not. Not even any air blowing out of vents and it is usually very strong and cold when on.  Need help asap please. 

[Pmw9554]

C wire is connected just fine. AC been running great for a year but all of a sudden nothing…