Looking through the threads, I haven't found anything quite like what I'm experiencing. So if there's already a post out there on this topic, I apologize. I have a dual zone heat pump system, and both units are approximately 14 years old. On a normal summer day (70s to 80s) my air works fine. However, when it gets into the high 90s (usually accompanied by high humidity), the condenser that feeds the upstairs will just shut off for hours at a time. The air handler will still run, but all I get is warm air. Once the day starts to cool off toward the evening, the condenser will start back up, and everything is fine afterwards. I just had the unit serviced for its 6 month, and a leak test was performed also, but no problems were found. 1lb, which I know isn't much, of R-22 was added as well.. . And of course, when someone comes out to troubleshoot the problem, no one can find the culprit. Any suggestions would be greatly appreciated!

This could be the cause of your problem, it sounds like heat is a possible problem and one of the things that heat does is make the compressor over heat and it will not come back on till is has cooled. Two things can make the compressor over heat one is an over charge of freon, the other is not enough air going through the fins on the outside condensing unit. First turn off the units power and then use a water hose and wash all of the coil on the outside unit. Let dry for a while and then restart the unit.. . Hope this is the problem.