While in the crawlspace under my house today, I saw a few things that caused some concern. 1) The seams on the flue pipe are showing signs of corrosion 2) Water was dripping from the transite pipe, and 3) The transite pipe is being held in place by a wood bracket and is deteriorating because of the drip. It rained fairly hard the past couple of days but had not been raining for about 8 hours when I went under the house. I looked in the attic and did not see any sign of water infiltration from the roof end. I am going to have a few HVAC specialists give me their opinion/estimate, but I was hoping to get an unbiased opinion here as well.
I was told by my home inspector when I bought the house 5 years ago that the angle of the flue pipe from the furnace to the transite pipe was too shallow. Whoever did the installation used the original c. 1942 transite pipe from an old wall furnace rather than run a new pipe because it was cheaper and easier. I have a carbon monoxide alarm inside the house and thankfully it has not sounded.
I'm guessing that the HVAC company will recommend running a new vent pipe to the side wall of the house and up the exterior and through the eaves. Removing/replacing the transit pipe would be costly and would not correct the vent pipe angle issue. Any idea how much this would cost? Please see pictures. And, yes, the rat issue has been remediated but not before they damaged the duct insulation. Many thanks for your thoughts and suggestions.