enter image description hereFirst 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:

   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.

  • 2
    Is there some reason you aren't telling us what furnace or heat pump the Nest is connected to? We have some experienced HVAC folks around, but they aren't psychic. :) – isherwood May 7 '18 at 19:24
  • Wow - well, I am at work right now. Thought I could get someone to help out. Apparently, it's impossible to answer without that part of the equation. My apologies. I have a picture of the wiring from the furnace unit. Not sure if that would kep any. But, let me know. – ETedford May 7 '18 at 19:38
  • 1
    Not impossible, just better likelihood of correctness. Add it later when you can. – isherwood May 7 '18 at 19:43
  • Are you getting any diagnostic blinking-light patterns/codes on the furnace when the thermostat calls for cooling? – CactusCake May 7 '18 at 20:33
  • 1
    Regarding the individual asking about the make of the furnace....The furnace is a Lennox Pulse21V gas furnace. The a/c unit is Carrier Model 38ESG or 38EZG. (Both listed on the user manual). – ETedford May 7 '18 at 23:53

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!

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The easiest thing to do would be to jump the RH and Y terminals at the thermostat then go outside and see if the outdoor unit comes on. If it does the problem is with the thermostat. If it doesn’t the problem lies elsewhere. If you jump the wires and you get a feint hum coming from inside the outside unit then the problem is likely with the outdoor unit. Check for power. If you are getting nothing while jumping the two terminals it is most likely your wiring

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  • Thanks. I will do that tonight and, at least, I'll have an answer. Appreciate it. – ETedford May 8 '18 at 17:06

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