I think there is a refrigerant leak somewhere in your AC system. When the refrigerant pressure falls below a certain value, the expansion valve/control will not energize the compressor clutch. This leak could be anywhere. Often, its a seal leak on the compressor, but since this was changed out twice, the leak must be somewhere else (assuming good connections were made for the changed parts).

The best place to ask is your local repair shop, one that is certified to handle and dispose of refrigerants. Depending on the type of failure, the entire sysem may Need to be flushed to rid it of any debris. Little pieces of stuff can ruin a compressor. If you do not know the history of the repair, that 'after market' compressor may have been a usesd one from a salvage yard. It could also have been a rebuilt or remanufactured unit. A rebuilt is that has been refurbished by replaceing the obvious failed parts to make it work again. A re-manufactured unit has been taken apart and all parts worn out of specifiaction replaced. Questionalble bearings and seals are replaced. A re-manufactured unit, on the average, is better than a rebuilt one. However, both will contain used parts and may not have the same life as a new one.

To Answer Mr_HAVAC's question Problem: The A/C quits cooling when the temps reach approx 90 degrees. The fan keeps blowing air, but it is warm air. I have been without A/C for a year except for a room A/C. Right now it is 105 and it was up like 116 last summer. Repair History: May 2006 - Condenser fan replaced because it had been installed backwards. July 2006 - Relay Switch Replaced Sept 2006 - Condenser Replaced No more 90+ days occurred because it was Fall May 2007 - Relay Switch Replaced Again June 2007 - Assessment is compressor override kicked in at 90 degrees - need to replace unit. I have a 1350sqft 1 story home - I bought it before I lost my husband, I'm trying to keep it. I'd like it to be cool enough to live in (sigh) ------------------ As to the issue of 2x4 etc. I have been on the phone all day with: State Licensing Board State Insurance Commission County Blding Dept Warranty Company Besides reading docs and laws on the web. County said don't worry about the license, just get owner/builder permit. State says illegal to get owner/builder permit plus I would be libel for workmans comp, insurance claims etc. If anything goes wrong. I could indeed lose everything. I will not go owner/build permit. State Insurance Commission is sending me a complaint form in the mail. When I pointed out the isssue to the warranty co. they said they'd known for a week and dropped the A/C Co but since they were already working my issue they didn't catch it. A/C Company says they now have the insurance straightened out. Warranty Company says too bad. We must now start over with a new company and see what their assessment is. . . . So now I wait for the other Company to call me some time next week. And just how do I know who to trust and what is a fair price for the work etc. Thanks to eveyone who is trying to help.

I'm with Jake, I don't think that is what killed the compressors, if indeed they were dead in the first place. Lint could surely clog the condensing coils over time but you would have noticed the unit not cooling most likely long before it caused damage. However, if it is a concern, I would suggest you move the vent as Jake suggests.