House not cooling down (3 wire cool-only system)

[Golivefree]

I have a very simple cool only system. There are 2 AC units, each with its own thermostat. 

Original Thermostat has 3 wires: Rh (with jumper to Rc), G, and Y. 

When I first wire the nest, the tests work. Cool blows cool. Fan turns on. After setup, it works like it should for a few seconds, then the AC turns off and fan just blows. House will then begin to heat up slowly since no cold air is coming in. 

I went through an hour of troubleshooting with Google. Their end recommendation was to return both units. I find it very hard to believe both units are defective.

Troubleshooting done:

1) Ensure compatible of unit and wiring

2) swap G and Y wires. This forces ac on. This works just fine. AC stays on. 

3) Switch wires back to correct spots, AC turns off shortly after. 

4) Battery seems to be slowly draining, so we tested after charging by USB cable. 

Any ideas why the AC turns off?

AC Make/Model: International Comfort Products PGD436090K000E1

Original Thermostat: PRO1 T705 Single Stage NEW AL AC Air Conditioner Programmable Digital Thermostat

 

 

[CoolingWizard]

@Golivefree , how long did you charge the display using USB cable and charger?  Is there any chance there is fourth conductor wire in the wall behind the thermostat? It would be great if we could hook up a power common wire to ensure there is enough charging current available.  When the air conditioner is running, there is no charging  current available.  

AC Cooling Wizard

[Golivefree]

Thank you for getting back to me. I'm actually ordering a nest power connector today to see if that fixes the issue. I charge one of them all night long and still experience the issues the next day. We left for a couple hours, but when we came back, only the fan was on and no AC.

Power connector should arrive tomorrow. I'll update then.

[zoeuvre]

Hi folks,

@Golivefree, thanks for reaching out to us, and I'm sorry to hear about the situation. I want to check if you have already received the Nest Power Connector you ordered. If so, how does it go? 

I appreciate your help, @CoolingWizard. 

Best,

Zoe 

[Golivefree]

I installed the power connector and problem solved! Thank you for the recommendation,

[zoeuvre]

Hi folks,

@Golivefree, awesome! I'm glad that everything has been sorted out. If you have questions or concerns in the future, feel free to start a new thread, and we'll be happy to help.
 

All the best,

Zoe