Cool setting doesnt turn on A/C

[Jaymie]

When the cool setting attempts, it blows lukewarm air for a few seconds then stops. Our A/C unit does not turn on during this time.

I have already tried:

• Restarting the thermostat
• Moving my W wire to the OB slot
• Making sure all wires are connected properly

Here is a photo of my old thermostat and my current wiring. 

 

 

[CoolingWizard]

One of the first problems you have is that the Nest back plate is not designed to accept stranded wire.  It only accepts an 16 or 18 gauge solid conductor wire.  Standard HVAC a thermostat cables are 18 gauge solid conductor. The second thing is your wires are soldered and soldered unevenly.  

AC Cooling Wizard

[Jaymie]

Thanks, I chatted with a nest customer support agent who told me the same so I have an appt to get the wiring changed. What do you mean that the wires are soldered? I can see they used to be soldered on my old thermostat, but I don't see soldering in the nest setup. 

[CoolingWizard]

The first picture posted on the thread creation shows stranded wires with soldered ends being placed into the Nest Backplate. If your AC is not working, double check the control board 3-amp fuse.  If you did not turn the power off before removing wires, you might have created a short and blew the fuse. 

AC Cooling Wizard

[Jaymie]

As an update, I found out the stranded wires were connected to the actual ones with a wire nut, so I just removed the stranded ones and used the actual ones. The A/C still isn't coming on 

 

[Jaymie]

For any future folks reading this thread, I had an ontech specialist look twice and they ultimately gave up saying the system must be incompatible. I then hired an HVAC expert who found a shorted fuse in the A/C. All works now!

[CoolingWizard]

@Jaymie , since the ONTECH technicians were not a qualified HVAC technicians, you should demand a refund since the problem was not due to incompatibility.  He should have verified the AC power from the HVAC equipment was present and then replaced the blown fuse.  

AC Cooling Wizard

[Jenelyn_O]

Hi there,

Thanks for reaching out. I'm glad that it all sorted out. I hope you get the answer you're looking for. Please let us know if you still have questions or concerns, as we'll be willing to assist you. Otherwise, I'll be locking this thread after 24 hours.

I appreciate your help, @CoolingWizard.

Best,

Jenelyn