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Discussion Starter #1
I've done a bit of research and still can't find a solution. Our AC system blows fairly strong and cold downstairs but barely blows at all upstairs. The house is a little over 3 years old, and approx. 1350 sq. feet. There is an Aprilaire zone control system in the attic wired to the 2 thermostats (I'm assuming) and the air handler and a wire running to a duct coming from the air handler that runs to a large box with several runs of ducting coming out of it. My guess is there are dampers in the ducting that should be controlled by the zone control system, but nothing I've done seems to change anything. I've reset the zone system and also tried turning off the downstairs thermostat to no avail. The AC unit is on almost continuously, but still blows very little out of the upstairs vents. I'm fairly handy, but don't know much about HVAC units. I also don't want to call someone and have to spend the $$. Help, it's flippin hot!
 

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Good chance the second floor ducts are undersized.
Or, the second floor damper isn't opening the whole way.
 

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Discussion Starter #3
The ducts seem to be fairly good size. It's not a very big house and the ducts appear to be in the 18-24in range. My guess is the dampers aren't opening, but they seem to be controlled by the zone control system without an obvious "manual override." Is there a way to manually open them or get them "unstuck?"
 

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Some have a manual lever on them.

The main may be 18", but what size are the supplies goping to the rooms.
 

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Discussion Starter #5
The ducts to the rooms can't be smaller than 12". If there isn't a manual lever, is there any other way to disengage them and leave them open?
 

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If they are flex ducts. The outside diameter, isn't the size of the duct.

Some don't have a manual overide.

In that case, other then removing them, no way to overide.

Check your warranty. Might have a 5 year warranty on the dampers.

PS: If you overide the dampers for the second floor. Then the second floor will get heat or cooling when ever the first floor calls.
 
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