I have been told that my heat exchanger on my GMP125-4 furnace has 4 or more cracks by a certified technician.
This furnace is 11 years old, so I am trying to determine if I should pay to have this replaced or buy a new furnace.
How much effort would it take to replace this myself? Where might I find instructions for doing so? Where can I buy a heat exchanger on-line?
Thank you.