Restricted, crimped air ducts?

Jeff Eastman · 05-30-2007, 10:24 AM

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**DavidR** · 05-30-2007, 03:25 PM

Jeff,

It wouldn't be a bad idea to recommend that they have the static pressure of the duct system tested to verify proper airflow.

Any equipment attached to a duct system like that is in for a rough run.

**DavidR** · 05-30-2007, 03:34 PM

If you need a contractor in Vegas that does performance testing I can hook you up Jeff.

One of the guys who mentored me lives in Vegas.

Joseph Rago · 06-01-2007, 09:42 AM

As a rule, flexible ductwork should not be installed in lengths greater than 8 feet, and with a bend greater than 90 degrees. One could test for "static pressure", but where? Suggest testing for volume delivered at each outlet for a more definitive result.

Joseph D. Rago P.E.
A.E.G.
Yardley PA

**DavidR** · 06-01-2007, 02:46 PM

You could test the total external static pressure to see how much resistance the fan is seeing & you could also measure the static pressure drop of each suspect flex run out.

Most guys can afford a manometer or magnehelic, most don't have anyway of measuring air volume from the registers.

**Jerry Peck** · 06-01-2007, 08:37 PM

Originally Posted by Joseph Rago

As a rule, flexible ductwork should not be installed in lengths greater than 8 feet,

Where is that information from?

Would like to read it.

I know that flexible "air connectors" are not allowed longer than 14 feet, but "flexible duct" length is unlimited.

Thanks.