I had to pay $920 to replace a 5year old heat exchanger due to cracks in all four heating tubes.Each tube was cracked in the same location.` My observations of the cracks look like a manufacturing defect in the crimped aera at the entery of the heating tube. The technician informed me that he gets 2or 3 of these a week with the same cracks. Also the parts he put into my furnace are exactly the same as the original.The dealer is returning the cracked tubes for your review Please call me at 219-627-****. What parts and labor warranty is on the replacment parts?