Using manometer for duct smoke detector test

[SB63]

What is the best way to check a duct smoke detector for pressure differential? It appears that a magnehelic differential pressure gauge is used, but can a regular water manometer be used? I check manufacturer data sheet and it stated that pressure differential can be checked with filters on the probe tubes. How is this done? Thanks

 

[imok2]

All you need is here

http://www.systemsensor.com/html/guides/A05-1004.pdf

 

[SB63]

How do you hook up the magnehelic gauge hoses when the filters are in place?

 

[ChasBean1]

The detector housing usually calls for it to be placed in an airstream of at least 400 feet per minute. This produces a velocity pressure between the two tubes of around 0.01 in. w.c. You can't measure this difference with a typical U-tube manometer just because this height difference is invisible to the eye. A 0-0.1 in. w.c. inclined manometer would do it, but your best bet would be a digital manometer that reads at least down to 0.001 in. w.c.

The part about filters on the probe tubes probably just relates to dampening oscillations from turbulent or erratic flow in the duct.

-CB