Thread: Vent issues for high efficiency furnace

This is a KeepRite high efficiency (90%) furnace (Sorry for the blurred image). From the two pictures we can see the pipes go down to the crawl space, come up and out of a wall. The intake pipe is less then 1 foot high. The exhaust pipe is about 2.5 feet high. So the problems are
- the intake is too close to grade, it should be at least 1 foot high.
- if venting to walkway, it should be at lease 7' high.
- the intake and exhaust are too close, should be at least 3' apart.

Thank you in advance for your comment.

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Originally Posted by Matthew Liang

This is a KeepRite high efficiency (90%) furnace (Sorry for the blurred image). From the two pictures we can see the pipes go down to the crawl space, come up and out of a wall. The intake pipe is less then 1 foot high. The exhaust pipe is about 2.5 feet high. So the problems are
- the intake is too close to grade, it should be at least 1 foot high.
- if venting to walkway, it should be at lease 7' high.
- the intake and exhaust are too close, should be at least 3' apart.

Thank you in advance for your comment.

Good workmanship there... Generally the intake and exhaust pipes should be above the snow line and no farther than 3' from each other. The reason for this is if too much of a atmospheric difference exists between the pipes, possibly from wind, the furnace will not start or it will shut down. Some installations have them horizontal with one facing out and the other facing down. They should drain into the furnace. The is to prevent the condensation from the furnace freezing in the pipe creating an ice backup that will shut down the furnace. Seen installation that even this didn't work and the pipe had to be insulated to stop the freezing. This installation needs to be moved up past the maximum snow line for the area, correct that beautiful exit work on the wall, and generally follow the manufacturers installation instructions. You didn't note, but how far are these from openings in the wall (windows, doors) both horizontal and vertical, and intake venting for other devices? There are restrictions there too.

Dunno about this manufacturer, but my furnace (Carrier) specifies a maximum number of bends in the intake/exhaust piping. I'm guessing this one may be pushing the limit.

Originally Posted by thaddeus cox

Dunno about this manufacturer, but my furnace (Carrier) specifies a maximum number of bends in the intake/exhaust piping. I'm guessing this one may be pushing the limit.

Good catch!

What happened to the exhaust vent being pitched back towards the furnace to drain to the condensate? I'll take a wild guess that someone didn't read a manual.

1. Haven't seen any installations like the inside portion. Wow. Don't know of any manufactures instructions to allow this type of installation.

2. The sheet metal and screws and flashing blend in well, very professional - not!

3. The three foot rule distance from intake exhaust I am not sure that is an issue dependent on some manufactures exhaust/intake set ups.

Agreed, the number of elbows was the first thing I saw. Followed right behind with the huge trap that has been created, not sure which is exhaust or intake, but you have pipes going down and then one turns up, wonder how much water is sitting in there.

Not sure about the walkway issue, if it is a private residence. I’m guessing with the hose reel and black pipe sticking out, this looks like a simple pathway along the home.

That sheet metal work is first class... lol

Was there a condensate pump down in the crawlspace where the pipe hit it's low point?

Is the 7' rule for venting at walkways in place to minimize potential vent damage or to protect against burning the skin of passers by? (My understanding is that the gas is low temp)

Originally Posted by Luc V. L.

Was there a condensate pump down in the crawlspace where the pipe hit it's low point?

Is the 7' rule for venting at walkways in place to minimize potential vent damage or to protect against burning the skin of passers by? (My understanding is that the gas is low temp)

Thank you, everybody, for your comments. I came to that house again and had a look in the crawlspace. As you can see from the picture, there is a condensation line that dump the water into a hole on the crawlspace floor.

The two pipe openings are on wall, a private walkway to the backyard. The intake pipe opening is about 1 foot above ground. And the exhaust opening is about 24'' above the intake.

Originally Posted by Matthew Liang

Thank you, everybody, for your comments. I came to that house again and had a look in the crawlspace. As you can see from the picture, there is a condensation line that dump the water into a hole on the crawlspace floor.

The two pipe openings are on wall, a private walkway to the backyard. The intake pipe opening is about 1 foot above ground. And the exhaust opening is about 24'' above the intake.

1' above the ground? I assume you get snow where you are and it drifts.... need I say more?

As for the "drain"... see the attached strip. (Wonder if the pipe filled up with water and they "fixed" it with the drain?) Double

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Appears multiple occurances of unqualified modifictions to systems and unqualified, unpermitted replacements.