Furnace Venting

This is the first time I have seen this. Newer Trane furnace vents up through the roof and in the attic area, they merge together to a single vent. Is this a proper installation method?

I would need to see the manufacture’s installation instructions myself.
What is the second pipe ?

Sorry, I should have noted that. One is the intake and the other is the exhaust. The furnace is less than 5 years old, but the instructions were not available.

I’ve never seen or heard of the intake and exhaust being connected together, but then I’ve never installed Trane equipment.
I don’t see how that could possibly work.

This is a very common installation. They don’t actually vent together. One pipe just runs inside the other so that you only have to put one hole through the roof.

Exactly…quite common installation.

Ah ha, that makes sense now then.
It must be a special wye fitting.

Picture is upside down.

**Vent Termination Kit **

          Concentric Vent Termination Kit, 3 Inches     
                                                                     Grainger Item #                 6MC43                                                             Price (ea.)                 **                                                                   $67.50                                                                                    **                                                                                                 
                                         Brand                                         DAYTON                                                                                             Mfr. Model #                    6MC43                                                                Ship Qty.                                                       [http://images.grainger.com/images/icon_help.gif](http://www.grainger.com/Grainger/items/6MC43#)                                                                                    1                                                                                                          Sell Qty. (Will-Call)                     [http://images.grainger.com/images/icon_help.gif](http://www.grainger.com/Grainger/items/6MC43#)                                  1                                                             Ship Weight (lbs.)                 5.0                                                             Usually Ships**                     [http://images.grainger.com/images/icon_help.gif](http://www.grainger.com/Grainger/items/6MC43#)                                                       [Today](http://www.grainger.com/Grainger/items/6MC43#)                                                                              Catalog Page No.                                                                                            [3219

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Installation sheet

Thanks everyone…It was a good day, I learned something.