Metal Flue Cold Spots

[John Evans]

Any thoughts for the apparent cold areas shown at the furnace flue? Obvious moisture issues. Metal flue connects to a transite flue visible in the attic.

[Brandon Clark]

I'd definitely say the corrosion build-up areas would cause some different heat readings. I'd also imagine your reading the heat from several other areas in the room due to reflection and the metals emissivity.

Sorry I can't help as I don't know exactly what the problem is that your trying to identify.

Thanks for posting the pics though. I always like viewing other thermographers images.

[Charley L. Bottger]

Was either of the gas appliances in operation at the time when the image was taken and if so how long

[Peter C. Russell]

Did you take any images from different angles? other side of the pipe?

[John Evans]

The gas furnace was running for about 20 minutes, had shut it down just before taking the images. Water heater was on.

[John Evans]

No other infrared images.

[John Evans]

Following a very nice converstion with Chris Seffrin, although the flue has moisture problems, the "cold areas" are reflectance from the cleaner flue surfaces. An unsolicited plug for Infraspection, they are fantastic.

[Brandon Clark]

Originally Posted by jevans

Following a very nice converstion with Chris Seffrin, although the flue has moisture problems, the "cold areas" are reflectance from the cleaner flue surfaces. An unsolicited plug for Infraspection, they are fantastic.

Wouldn't what is said above be the same as "I'd also imagine your reading the heat from several other areas in the room due to reflection and the metals emissivity."?

[David A. Andersen]

It has nothing to do with temperature, everything to do with emissivity and T-Reflect compensation.

Subscribing to the "I only do qualitative thermal scans" being taught around here leaves you out in the cold when understanding these thermal signatures, doesn't it!?

Another interesting concept; a level III thermographer "does home inspection"!

Yes; the Seffrin clan is a wealth of IR information.

http://www.thermalimagingscan.com/In...r-Training.htm

[Robert Ernst]

The moisture is more than likely due to the transite pipe. The transite doesn't heat up like the metal and causes cendensation. Thats why you have the rust at the bottom and probably inside the furnace as well. The newer furnaces don't have as hot of flue gases so the metal piping is required. I have heard of some areas allow the transite to be used as a chase for a single wall metal pipe. Another problem with the transite is that is can cause spillage.

[John Evans]

Another interesting concept; a level III thermographer "does home inspection"!

David,

I'm not sure what you were referring to with this statement. Should I continue my training to level 2? absolutely yes I do hope to attend a level 2 course soon Any inspector using thermal imaging would benefit from advanced training. The images posted were taken out of curiosity on my part, I typically do not image flue pipes.

The transite pipe appears to have a defective seam, with water stains at the surface of the seam. Condensation is an added problem.

Thanks for your input.