[sxiong]

The problem started about a week ago.

The A/C didn't blow cold air when thermostat showing "cool on". It happened in the morning. I went to attic to reset the unit (by switching it off then back on), and at the beginning it solved the problem.

Then after a couple of days, it happened again, now even resetting the unit didn't help. I randomly touched the R,G,W,Y,C wires and heard the click sound, and fan started blowing, and it kept running fine for the rest of days.

I called a repair company. They told me since it's working sometimes and sometimes not, it's better for me to wait until it totally stops working.

So I repeated the same trick almost every morning for the past week. And this morning, nothing worked, no matter if I reset it, touch the wires, I could hear the click and motor started, then it went quiet in about 2-5 seconds. The red light flashed steadily and slowly. I thought it's totally dead and I called the repair company. They said they would stop by around 2:00PM. Of course, they were caught by something else. Surprisingly, the A/C started working perfectly normal around 3:00PM, without anyone doing anything. Then the repair man showed up around 5:30PM, got mad that A/C's running, but I didn't tell them.

Here, I have two questions:
1) where would you suspect the problem is?
2) Should I wait when the unit's totally dead to call for repair?

[sxiong]

Forgot to mention, the unit is Lennox 80MGF series.

Thank you very much for your help

[Joshdta]

So when it is not working, neither the indoor blower or the ac unit is running? Sounds like a bad control board, or a bad t-stat.