Cat IV Vertical 2 Pipe Venting

[Mike Lamb]

The direct vent requirements for this furnace call for the two pipes to be installed horizontally. What are the practical concerns with this set up of the pipes being installed vertically?

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[Jim Katen]

The direct vent requirements for this furnace call for the two pipes to be installed horizontally. What are the practical concerns with this set up of the pipes being installed vertically?

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I don't know. Never seen one that didn't allow for vertical vent pipes.

[Mike Lamb]

I am not sure I have ever seen vents installed vertically. Anyhow, the manufacturer's instructions for this model furnace says the vents should be installed as shown in their diagram which is a horizontal installation.

I was wondering if this is anything to get worked up about.

[Mike Lamb]

I just talked to a Ducane tech and he says it's not a problem.

[Tom Raymond]

Those look horizontal to me, or are you referring to the elbow?

[kurt]

Due to People's Gas restrictions about venting into any gangway <10', just about everyone is now running them up through the roof. There's nothing wrong with vertical installations according to the guys I work with. I looked it up a few years ago, and found nothing that says vertical is a problem.

[Mike Lamb]

Those look horizontal to me, or are you referring to the elbow?

No. I'm talking about a vertical wall install with the vents on top of each other rather than side by side.

[Tom Raymond]

Ah, now I see it.

[kurt]

Makes no difference. Why would it?

[Mike Lamb]

I was wondering if the instructions and illustrations which always shows the vents side by side had a good reason for this. I would think you would not want the exhaust located directly below the intake, for instance.

I know it makes practical sense to vent side by side since most often the furnace is vented from the basement just above the foundation in wall installs.

[David Meiland]

If you did everything perfectly wrong, with the exhaust above the intake, condensate could drip into the intake. You would have to be exceedingly clever to screw it up that badly, but it could be done. In any case, they figure you're going to run two pipes side by side on the ceiling, or in a joist bay and out the rim... horizontal.

[ejager]

I'll right, I'll bite. Why are there three pipes?

They tried a few vertical installations in my area but it they always seemed to have problems. Could be the long runs from the basement up through two floors and then an attic. Bigger vent piping didn't overcome the problems.

In the extreme cases, the 'open concept' plans presented by architects never included a chimney chase and so the HVAC installers always had multiple jogs and horizontal runs as well.