Somethin is just not right !

[Richard D. Slocum]

OK , here is the weirdness of the day! 2001 Amana GFA furnace. Turn thermostat on, furnace kicks on, flame looks great , blower is quiet, everything seems to be working fine. So I walk around to check air flow from the vents and guess what? Heated air is coming from the cold air returns and the floor registers are sucking air back to the furnace ! These people have been living in this house for 9 years with the furnace working backwards!

Question: What would cause this?(I know it's not my job as an Inspector to determine cause, I just would like to know). Could the blower be wired wrong and running in reverse? This is the first time I've come across something like this.

[Jeffrey R. Jonas]

Did you check the air flow at the filter to confirm it is a blower issue, and not a screwed up duct install?

[Larry D. Kage]

Originally Posted by jjonas

Did you check the air flow at the filter to confirm it is a blower issue, and not a screwed up duct install?

If you do what Jeff asked about, then you'll have a better idea what's going on.

Otherwise, it is hard to tell without more info.

[Richard D. Slocum]

It is a Horizontal draft furnace in a crawl space. My original thought was that they have the duct work installed wrong(reversed)! But then I thought, how could they(HVAC contractor) screw that up and not notice it! Oh well , it's been called out and the HAVC guy can figure it out.

Thanks guys!

[David A. Andersen]

If they replaced the blower motor and wired it to run backwards, there will be little or no reversed air flow.

The motor direction can be reversed with two wires.

I'll put my money on the duct is switched.

Is this a packaged or split system?

[Richard D. Slocum]

Yeah , your right about the blower. The way the fins are configured there wouldn't be much air flow. It is a packaged system. I'm thinkin the ducts are switched. Thanks David !

[David A. Andersen]

That is the first question we must ask when changing out a pkg hvac unit? What side is the supply?

If it is not on the same side: is there room for a transition?