[URY914]

The facts: Typical split system home a/c unit, about 30 years old. Still has the old mercury t-stat. Works OK but I hold my breath every time the seasons change from heat to a/c.

Today's problem: My wife leaves the house at 7:30 am and I get back at 11:00am, I open the door and feels like it is over 100 degrees in the house as if the heat has been on. Poor dog is looking at me with her tongue hanging out. The unit is running but the air is HOT. The stat is set in "auto-cool" position. I turn it to "off" and start looking for the problem. I find nothing. I wait a hour and turn it on. COLD AIR! It has now been running for about 4 hours and has cooled the house down to a normal setting.

So WTF? Should I make the $1000+ phone call and get the service guy out?