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ICE

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Joined
Jun 23, 2011
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13,887
Location
California
23619657205_c7e5307112_b.jpg
 
Look at how that flex duct pinches down on the far left. In theory, an oblong/oval duct will have roughly the same cross section as the round duct.

In practice, this happened on one of my projects, and it restricted the airflow. I did not initially see the pinched duct installation; it had already been covered with a drywall ceiling. But shortly after occupancy, the fan coil unit was icing up, and we figured something must be blocking airflow, so they had to tear out the ceilings until they found the pinch point.
 
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