I am finally getting around to cleaning out our furnace, and trying to evaluate what it may need in the near future. I noticed a lot of rust around the holes going into the heat exchanger, and a pile of flaked rust laying under the burners, I'm just wondering if this is typical for this type of furnace, Thanks<br />...<br /><a href="https://www.youtube.com/watch?v=S-X1EIB0FwI" target="_blank" rel="nofollow">https://www.youtube.com/watch?v=S-X1EIB0FwI</a>