Please.. If you own an Eagle1/Husky or Eagle2/Polar check the condition of your pot liner on a regular basis. The owners manual says it should be checked on a monthly basis during the heating season and replaced as necessary.
Every year I talk to people that have a 5,6,7 year old furnace that has a cracked heat exchange because that liner was never checked and allowed to fail.
The pot liner sells for $82.61 or $108.18 depending on if you have the Husky or the Polar.
A new heat exchanger is $1652.31 or $2969.22