I hope my request for help doesn't violate the site rules, but I think I need the advice of a professional, and this seems to be the place to find them.
Our five year old A/C unit went out (nothing would come on) this past weekend and to make a long story short, the tech that came out claimed that after he blew the transformer he had just replaced, he realized the problem was actually a bad controller board, a Carrier HK42FZ013. This was this past Sunday. He was to return on Monday after he got a new board and and new transformer.
He arrived late yesterday and proceeded up to our attic. I was already a bit suspicious, but my instincts really started flairing when he was in our attic for almost two hours replacing it. Access to the controller board is fairly easy on our Carrier 58STA070, so I couldn't understand what the problem was. He finally got the unit operational, I paid him and then asked for the old board. He first told me he had already taken it out to his truck, and when I said I'd like to have it, he refused, saying he couldn't let me have it - company policy. We were still inside the house and I could see the box on top of his tool bag despite what he had said and, well, I took it and refused to give it back to him. I figured it was still my board, whether it was a dead one or a live one. Of course my suspicions deepened as he insisted I return it to him or he was going to go up to our attic and remove the "new" one. I was polite, but explained to him that that simply wasn't going to happen and invited him to call his boss or we could call the sheriff, but he wasn't leaving with my control board. I have the board.
My suspicion is that I now have in my possession a perfectly good control board. I even wonder if I am holding the brand new board that, after discovering it wasn't the problem, he continued to trouble shoot. That's the only reason I can figure why he was so adamant about leaving with it (and perhaps cover himself in the process).
Anyway, I am hoping somone here can offer me some guidance on what I can and should do at this point.