Thread: Combustion Air?

Saw this today, recommended they have the intake ran outside. It’s in an unfinished basement…ok as is? Looked at the installation manual taped to the side and it shows outside venting for both.

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50 cubic feet per 1000 btu is a guideline for combustion. Feed looks to be through cold air return.

Originally Posted by Terry Ewald

Saw this today, recommended they have the intake ran outside. It’s in an unfinished basement…ok as is? Looked at the installation manual taped to the side and it shows outside venting for both.

You are correct, it should be installed per the instruction manual. There is no good reason not to.
That is one of the good features of that furnace, that the intake can be run with the exhaust out to an exterior wall.

In my travels I have not seen a requirement for pulling combustion air from the exterior. From the photo I'd say that the installation is correct as an allowable option. Is it as efficient as it could be? No.

Thanks

Some furnaces require direct venting. Apparently, this Goodman does so you should flag it.

My Carrier Infinity 96, for example, also does. And as John K. says, there's really no good reason not to do it regardless.

Did it show it to the outside as an option or a requirement?

I quickly read over it and didn’t see anything mentioning notventing outside…just options for venting in confined spaces.

There are many "good" reasons to not run the combustion duct to the exterior. Cost and logistics are the primary ones. Since it is a goodman furnace my guess is someone was looking at the low bid.

One key issue when not running the combustion to the outside is the requirement for a screen or pressure device to simulate the ducting on the intake. The dang things have such a temperamental pressure switch in them that if the set up isn't done exactly how it supposed to be it won't run. My guess is that if it is running, you are good to go.

Terry, Is this a confined or unconfined space?

That Goodman furnace can be installed either as direct vent or non-direct vent. However, if installed as non-direct vent (combustion air does not come from the exterior), Goodman requires that at least one 90 degree elbow be installed on the intake air port (see below and attached). It is missing, so the installation is deficient. Of course, that is not withstanding the calcualtion of confined vs. unconfined space.

NOTE:

For non-direct vent installations, a minimum of one 90°
elbow should be installed on the combustion air intake coupling to

guard against inadvertent blockage.

Thanks....I've never seen one with just a 90 on it...but now I know.

No trap in the condensate line? Maybe its run 10 feet to a floor drain vs outside too.