re: A/C problem

quote:

---

It’s a nest. Service tech is convinced it’s bad wire. He changed several elect components after what we think was power surge or lightning. 24v power supply, relay etc. If you disconnect signal wire outside and reconnect it comes on and cools.

---

If you follow professional HVAC forums where HO questions are answered by experienced HVAC techs, NEST thermostats have a bad reputation and are known to cause issues that in many instances that can be fixed by changing the thermostat to a Honeywell or Ecobee. You might be better served in the long run in replacing your thermostat to a more reliable brand regardless what the problem might be with your unit.

LINK

Your techs comment on power surge is also a good reminder it might be a good idea to put a surge protector on the outdoor condensing unit, not complicated or overly expensive. I had one installed with my HVAC changeout this past Feb. In addition I added a whole house surge protector which will help protect the furnace and other electronics in the house with power surges, brownouts, etc. (refrigerator, washer/dryer, dishwasher, etc. - everything has a circuit board nowadays).