Sundstrand Recirculation Duct

[donv]

For several years, I have had an issue where I just couldn't get enough heat when it was really cold at altitude, especially at night. More recently, I have started to get lower pressurization numbers until I turned the heat up a bit.

Aero Air looked into it, and found the recirculation duct to be full of holes. This is one of those flexible, wire wrapped with fabric sort of large hoses, and after 40+ years, mine was crispy-- and where it made some turns, it was all full of holes.

Once we replaced that-- huge difference! Pressurization works better, and cabin stays much warmer. I would guess it probably cools better as well, but since I have freon air that is less noticeable.

[SKYFLYER]

I always thought the wire wrapped ducts were "time" limited items. Amazing that yours lasted as long as it did.

[donv]

There is no way to know how old it is (well, I could go through 40 years of logs and see if it was replaced at some point in the past, but I'm not going to). I have replaced previously one of the ducts (there are right, left, and recirculation), and we also replaced the cold air duct which goes to the overhead.

The right and left ducts are encased in fiberglass and not likely to have an issue, but the recirculation duct is a different story.