On November 2005, I bought and paid for (via Home Depot) a 2-Stage TUX060R93BW (XL-90) Trane Furnace but instead, A-1 Air Conditioning, the certified installer under contract with Home Depot, installed a SINGLE-STAGE, MUCH LOWER CAPACITY, LOWER PRICE TUX0C936D3 (XR-90). It was the Trane personnel who discovered the substitution. Also, Direct Energy which is currently maintaining the furnace found out that the pipes installed is smaller considering the distance of the furnace to the wall and length of the AIR INTAKE or OUTAKE; the reason the furnace keeps on 'dying.'
It my opinion, the substitution was either intentional or the personnel involved in this installation were grossly incompetent.
Instead of replacing the wrong unit installed, I accepted the refund of the price difference because I believed then that the owners have nothing do to with the substitution.
An Update:
Upon reading the above, Peter Messenger, A1 president, offered to replace the old Trane unit with a more powerful 80,000BTU Carrier furnace. And he did, last December 9, 2014.
Thanks to HomeStar.com and to Mr. Peter Messenger- There are really several good, caring people around us.