Electric Forced Air Furnace

Why would air be coming out of the cool air return in an electric forced air furnace? Thanks.

Are you finding this with the system on or off?

If it has air coming out the return when running then the fan is running backwards or has the wrong type squirrel cage atached.

If it has air coming out when off then you have a duct leak.

Squirrel Cage Blowers can pump backwards?

System is turned on, and cool air is coming out of the return. It feels like a fan.

Not anywhere near full flow but enough where you could feel some air movement.

Probably either squirrel cage has been replaced and installed backwards and/or motor is running backwards and/or squrriel cage is original and blades are missing and/or free-wheeling allowing the cavitation of air, giving the effect on reduced airflow and/or moderate flow back through the return system. I’ve seen all of the above , in seperate situations, but all are possible and probably other conditions I/ve never seen or heard about. A Pro HVAC Tech. should be able to figure it out though.

Squirrel cage blowers running backwards still blow in the right direction, just not enough.

There is not enough information to determine anything from here.

I still say there is something detached in there.

First is it a squirrel cage?

Is there more than one source of “return air”

More information is needed

Here is a real simple answer

If the fan is close to the return air and is trying to move more air than the system will handle some air will be forced out a close by return as an eddy current

In short more information needed - This might be normal for this system


You guys are whizzing against the wind here, to many variables could be any of a dozen reasons the unit needs more than just a visual look from the exterior.

Wha’ is dis "whizzin’ "? Is da win’ da same stuff comin’ out da hole in da floor?:stuck_out_tongue: :stuck_out_tongue:

Naw same as shoveling SHi! against the tide;)

Could be a number of things. Bypass humidifier problem. Barometric intake damper problem. Air to air heat exchanger problem. Too much to guess.

Electric furnace hard to have those problems???

No, not at all. These can be installed on any furnace to help with exchanging stale building air for fresh outdoor air. Not necessarily for combustion air, which an electric furnace obviously does not need. It’s pretty normal for a heat pump AHU, for instance, to have an air-to-air heat exchanger just for enhanced indoor air quality. Of course the forerunner to the air-to-air heat exchanger was the barometric intake piped into the return. On commercial work, this can just be a motorized damper to the outdoors into the return (non-barometric) with a “percent fresh air” dial on the wall in a closet someplace. The resi one’s were normally just weighted barometric dampers.

Are the HRV’s getting pretty common in your area now?

My thoughts were in relation to a normal electrical furnace with closed return. I have never observed a baromertic damper installed on a electric furnace just does not happen in this area. Now with a commercial install we are playing in a different ball park.

If you bring outside air into the return on a heat pump without a preheat you just killed your heat pump.

Okay-dokey. As the kids say, “Whatever!” :mrgreen:

My guess is… oh, nevermind. Sounds like you’ve got your mind made up, and there doesn’t seem to be much other interest in this topic, so I’m inclined to let it die.

Come on Buddy it takes two to dance. The only thing I decided about that particular furnace it needs a closer look.

TRUE, been there - done that.

If the blower is running, I don’t see how air can be coming out of the RA.
Seems to me it has to be drawing air in and maybe just feeling like it’s blowing out.

Maybe if the blower’s discharge air is completely blocked, it might be just churning air. ? ?

There is not enough info here to rack our brains on!

I have had more than enough fun with three phase motors running backwards because someone didn’t check. It don’t blow back. But low flow will freeze everything up.