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Nest Thermostat - AC not blowing

DunnDiego
Community Member

Just installed the Nest, I'm sorry I'm not sure what version. The box just says Nest Thermostat. Here is the item I bought from Amazon. Previously had a Honeywell Pro T705. 

Install went fine, Heating works (although not as warm as I recall before), Fan works, but the AC... nothing. The condenser/unit kicks in but nothing in the vents. I thought it might be the fan, but when I set it to fan only it works fine.

See attached pictures, sorry I didn't get before photos, but the original set up was pretty straight forward. Blue/Common was in C. White in W, Yellow, Green in Y G. Red was in RH with the jumper but new unit only has R.

TIA!!!

PS, I know I tend to strip down my wires farther than needed, but these are all well into the sockets and secure.

 

IMG_6281.jpgIMG_6282.jpg

7 REPLIES 7

Markjosephp
Community Specialist
Community Specialist

Hello DunnDiego,

 

Thank you for taking the time to let us know about your inquiry. I'd be happy to take a look at this for you.

Power issues, the wrong thermostat configuration, or a lack of service and/or service maintenance are some of the possible reasons why the equipment won't turn on. To isolate, please check your thermostat's power readouts on its "Equipment" settings. Also, some systems have a separate switch; check that the power from your HVAC system is turned on, including your AC.

 

Let me know how it goes.

 

Regards,

Mark

DunnDiego
Community Member

Hi Mark, thanks for your reply.

Like I said in my original post the AC unit does turn on when I switch the Nest to Cooling mode, but it doesn't blow any air into the vents. When I use Heat or the Fan on it's own, they both work and blow into the vents. All of my connections appear correct. 

The Equipment setting in the app doesn't show the cooling option, only Heat Configuration. Do I need to add something there? 

Markjosephp
Community Specialist
Community Specialist

Hey there,

 

I totally understand, @DunnDiego. Your thermostat somehow communicates with your AC unit, as it did turn it on, but no air is blowing. Also, the fan and heat work, so your system is definitely Nest-compatible. With this, we can see what could possibly be the issue. With power readouts, we can tell if it was a power concern. You can get this from your actual thermostat settings:

 

  • Settings > Equipment > Power Info.

 

I'll look forward to your response.

 

Regards,

Mark

Ok so I went into power info and it reads:

Vin: 35.170 V
lin: 385
PS: C-385

Markjosephp
Community Specialist
Community Specialist

Hello there,,

 

I'm sorry for the late reply, @DunnDiego. Thanks for the details. Let's sort this out:

 

  1. Try to reseat all the wires and make sure that they are properly connected and the tabs are pushed down.
    1. Note: Turn off the power to your HVAC system at the breaker box before touching the wires.
  2. Check the air filter.
    1. If your filter looks dirty or clogged, replace it with a new one.
    2. If your issue was caused by frozen cooling coils, you may need to wait for a while for your system to thaw before you can use it again.
  3. Check your drip pan or drain tubes.
    1. Like a glass of ice water, water droplets condense on the cold coils of your AC and drip off. Usually, this water drips off the coils into a drip pan and flows down a tube outside your home or down a drain. If your drip pan or drain tube becomes clogged and water starts to back up, your AC or heat pump may shut itself off to prevent an overflow of water.

 

If the same issue persists, please contact an HVAC technician to inspect your AC, as your thermostat is able to send a signal to your system but only your AC fails to blow any air.

 

Best,

Mark

Hi DunnDiego,

 

I'm checking back in. Were you able to do the steps above? I'd be glad to hear from you; I'd like to make sure everything is working.


Thanks,

Mark

Jake
Community Specialist
Community Specialist

Hey there,

 

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

 

Best regards,

Jake