In some cases the new homeowner will be denied coverage due to improper maintenance of the item, unusual wear and tear, improper installation, or against the building code installation. The homeowner can then contact his or her real estate agent or the real estate agent that represented the seller and complain. Real estate agents do not want to get involved with this problem; however, many of these same agents are the ones that suggested that the previous owner purchase the home warranty from the company. At least this will alert them that the warranty company may possibly have some problems.
Of course, as a last resort the new homeowner can have his or her real estate attorney file a suit against the seller for the cost of this problem. A word of warning here: things break, usually at the very worst time. Furnaces will quit when the weather goes subzero, and air conditioners die in the triple-digit heat of the summer.
Sometimes it is the age of the product, sometimes it is because the new homeowner forgot to do maintenance or did it wrong, and sometimes it is because the former homeowner messed up royally when installing the product. Figure out what happened before you run into court and incur legal fees. More than likely the item will need to be fixed or replaced before you get into court, so ask the person who repairs or replaces the item why it broke. Many of us have cursed the former owner only to find out that it was our own inexperience that caused the problem.