In future, PLEASE don't cross-post to alt.hvac AND home-repair.
The comments from the hvac people bleed over and are downright shocking to the sensibilities of us here on home.repair. When I see some of the vicious and profanity-laden missives, I get an attack of the vapors and the wife has to have a lie-down. The attitude on hvac seems to be epitomized by the Dilbert cartoon:
Panel #1 Dilbert: "I think it's the carburetor."
Panel #2 Mechanic: "You think it's WHAT?"
Panel #3 Dilbert: "I think it's the &#*^@! carburetor." Mechanic: "Well, why didn't you say so!"
Thank you for your consideration.