Fan Assist?

Does anyone know what this is? It appears to be a manual blower fan that is attached to the main duct run at the top of the air handler. It has two flex ducts going to an unknown location on the second floor.

My guess is that it is a fan assist that helps pull the air up to the second floor. However, it is powered by a swith on the wall adjacent to the air handler, and only turns on when you flip the switch.

I have never come accross on of these, so I thought I would get your feedback.



Heat Recovery Ventilator

Oops, I forgot to upload the images. Here they are…

RK6301-JCMazzara 037.jpg

RK6301-JCMazzara 039.jpg

I don’t think it is a HRV, but I could be wrong.


Looks more like a poorly installed booster fan.

looks like an exhaust vent booster, of sorts.

Looks to me like it needs some tender lovin’ care.:shock:

I especialy like the plastic flex line. It would be my guess that this is probably not allowed on the system.

From what you are describing and what you show in your photographs, it appears to be a device to circumvent the laws of thermodynamics.

You cannot air- condition two levels of the same structure with one HVAC air duct system without modification (zone control).

Warm air rises, cool air falls. Cool air will not go up to the second-floor and hot air on the second-floor will not go down to the first floor return air grill. This is an improper and likely an inadequate attempt to draw the dense cool air conditioned air to the second-floor.

Also, the thermostat is likely located on the first floor and cannot control of temperature on the second-floor which has a different heat load requirement. So, is highly unlikely that you’ll have adequate comfort levels on both floors from this system adaptation.

I’ve seen several of these, and had one myself. Looks like a booster. Unfortunately, if the booster only actuates by manually-flipping a control switch near the furnace / air conditioner, it’s not convenient at all. I have seen several booster fans wired-in directly to the blower motor switch. When the furnace (or a/c) is running, the booster runs. Normally, though, the booster fan is installed somewhere down-line on the plenum, closer to the room or rooms that require increased air flow.

It’s also possible that it is run by some sort of senser under normal conditions and the switch is either a manuel override, or the power source for the sensor, and it should be running when you checked the switch.

If this is a in line booster fan then this maybe installed in the wrong location. The booster fans I installed in my ducts require them to be near the register .

The other factor that concerns me is the fact that this thing is near the FAU.
Is the FAU a cat 1 natural draft unit?

Is this a closet install?

Space wise, confined or unconfined, for total BTU’s per hour. If for what ever reason that this “booster” fan draws from the closet it just maybe powerfull enough to draw combustion air/ dilution air from this closet and cause a back draft pull products of combustion / CO back down the draft hood and pushing it to the location this fan is installed for (if the ducting is not sealed)…

Possible , maybe could be …Just a concept here…:smiley: