Which side of the furnace should the return come into?

Old 11-19-12, 02:30 AM
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Which side of the furnace should the return come into?

I recently had my furnace inspected/cleaned and the technician mentioned that the return should not come into the back of the furnace because it could 'choke' the air supply. He said as a standard, returns should come into the side of the furnace...he wanted to charge me $500 to fix it.

Opinions please?

Old 11-19-12, 04:22 AM
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it can come into the back it is just not common. As far as "choking" the air supply..........doubtful.
Old 11-19-12, 06:04 AM
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Well, it can be an issue. Some manufacturers recommend that air supply to the furnace come to the bottom of the furnace rather than the back. That can be an issue with smaller BTU input furnaces, which can be pretty narrow.

But unless this were producing a problem of some kind, I probably wouldn't recommend a change. If the air supply were noisy, the fan was cranked up to a high speed, or the heat rise was excessive a change might be needed.

Another thing would be to look at the installation manual for the furnace and see what the manufacturer recommends for your furnace.

Do you have the installation manual for your furnace? If not, you might want to report the make and model of your furnace, which can be obtained on the rating plate of your furnace located in the burner compartment. We might be able to find it on line.
Old 11-19-12, 07:22 AM
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The reason you tech told you this is, because the air hits the back of the blower housing before it makes the turn into the squirrel cage openings. If he will build and install a new cold air drop through the side for $500, I say go with it. Most manufacturers don't allow cutting out the back of the furnace for the return, and you may be violating the manufacturers listing. When you do naughty things like this, you relieve the manufacturer of any responsibility.
Old 11-19-12, 07:39 AM
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By "choke" I wonder if the tech was referring to the air hitting the solid side of the blower housing instead of into the open ends?

Edit==I guess I took too long in replying

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