We have a 15 year old Payne 90-percent condensing gas furnace. The secondary heat exchanger has gone out due to corrosion (being installed at an incorrect angle), and although the part is under warranty, it will cost us big bucks for the service to replace it.

Our service tech is pushing us to go ahead and buy a new furnace based on the Payne's age and the typical lifespan he's seen with these models, but that will run us about 3 times the cost of just replacing the heat exchanger. It seems like there's a good chance we could get more years out of it based on the general lifespan of furnaces quoted on the internets. We've been in the house 4 years and haven't had any other problems with it. Opinions? Suggestions?