Furnace venting

[John Dirks Jr]

Shouldn't this exhaust/intake be facing opposite directions of each other? They are about 18 inches away from each other.

Also, that gas line you see in the pic was really rusty and the meter was outside on the wall right at the end of the driveway. Nothing to protect the meter from damage by a vehicle.

The AC unit in the picture had a core that was so dirty you could not even see the finns. I could have wrote a book on this place. Rotting fascia covered with aluminum. You know the story.

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[Terence McCann]

Did you get a make and model? Check with the manufacture?

I would say their far enough away from each other to prevent freezing the intake. You could face the exhaust upward (should be self draining) but I doubt there will be any problems with it this way.

[John Dirks Jr]

For the sake of conversation, what if they were too close to each other and both facing down, besides the potential to draw products of combustion back into the intake, what are other implications? I havn't heard the term freezing yet. What do you mean by that?

[Terence McCann]

The moist air from the exhaust goes into the intake, starts to freeze and can choke off the intake air as ice builds up. This was a big problem with hydro-pulse boilers early on.

[Richard Moore]

John,

I've not heard of the feezing issue before, but I could see how that could be a problem. Another issue in those tight quarters would be that you are "re-using" some air that has already been used for combustion and I'd expect the O2 content to be somewhat lower, which could lead to "less than optimum" subsequent combustion. I dunno how significant that drop in performance would be, but it would be a simple fix...so why not?

One other thing is that I suspect that A/C unit is going to rust out much faster with the moist (acidic?) exhaust blowing directly onto it.

I'd recommend turning the exhaust upwards...but not with an additional elbow, which would create a trap.