Exhausts house air?

[Peter Wigle]

Any idea what this is? Connected to the cold air return, warm air supply, and vented to the exterior (exhausts only - louvered vent). No wiring, no access to the interior - except by removing a duct. There is a humidifier connected to the cold air return below this - but doesn't appear to be related.

[Jerry Peck]

Heat exchanger for outside air.

[Peter Wigle]

Hi Jerry, That was my first assumption but how does it work? There is no intake. I'm familiar with the Venmar type where outside air comes in and takes heat from stale indoor air going out. This only blows out, so it would have to rely on leakage in the envelope to bring in fresh air. If it is supposed to bring in fresh air, it has the wrong type of grille (louvers).

[Michael Schirmer]

It's a home-made thing-a-ma-bobber with both bells and whistles. This would be one where I would describe it as non-standard ducting and inquire with the homeowner or installer regarding its functionality. Trust yourself - if it doesn't make sense, then it probably doesn't make any sense.

[Bob Harper]

US Plusaire (http://www.usplusaire.com/)

If no labels, could be a homemade version of this. If it is mounted on the supply, then it would exhaust whereas these units are designed to inhale outdor air into the return plus a smaller duct from the supply to temper the cold air so you don't get your delta T & ESP whacked out.

Bob

[Peter Wigle]

Thanks for the link. That is almost certainly what this is (a no-name version) - brings in fresh air, but doesn't perform an energy exchange. The system I looked at must have an improper grill - louvers will not allow it to draw outside air into the system - so I will suggest that possibility to the client.

[Jerry Peck]

That is almost certainly what this is (a no-name version) - brings in fresh air, but doesn't perform an energy exchange.

Peter,

Why do you say that?

Looks like it is connected in much the same way as the link Bob posted, and that serves as a heat exchanger.

[Jim Luttrall]

Peter,

Why do you say that?

Looks like it is connected in much the same way as the link Bob posted, and that serves as a heat exchanger.

Nope, not a heat exchanger. Just a fresh air induction device that tempers the incoming air with heated air from the furnace. The cold air is mixed with the warm air, not seperated by a heat exchanger.

[DavidR]

The idea looks great on paper but rarely do they work as designed.