Dwyer 460 - Manual

Bulletin H-10
No. 460 Air Meter
Operating Instructions and Parts List
The No. 460 Air Meter is a precision air velocity and
static pressure indicator based on the principle of the
variable area flowmeter. With the meter in a vertical
position, air comes in through the outer of the two top
connectors, passes into the scale chamber and enters
the tapered indicating tube at the bottom, causing the
white plastic ball to lift. Height of ball indicates static
pressure or air velocity.
Air velocity is registered from 260 to 1200 fpm on low range, 1000 to 4000
fpm on high range. Static pressure is .005˝ to .09˝ water, low range and .05˝
to 1.0˝, high range. To read on high range scale, cap exposed connector
with finger as shown in sketch. To read on low range scale, do not cap con-
nector.
STATIC PRESSURE—To read static pressure, secure angle connector to
meter with tubing supplied. For minus pressure readings, use center con-
nector on the meter. For plus pressure readings, use outer connector. Hold
meter vertically, inserting angle connector in unit under test, and read pres-
sure in inches of water on appropriate high or low range scale. For accurate
static pressure measurements in ducts and equipment having appreciable
air velocity, select a location where duct face parallels air stream and drill a
1/4˝ opening, leaving minimum burr. Secure supply grille probe to angle
connector, place over opening permitting as little leakage as possible and
read static pressure as above.
FURNACE DRAFT—Secure angle connector to center connection of Air
Meter with rubber tubing. Holding meter vertically, insert angle connector
into furnace combustion chamber for over-fire draft reading. For last pass
or smoke pipe draft, connect into the breeching on the furnace side of any
damper or draft control. To determine draft loss through furnace, subtract
over-fire draft reading from smoke pipe draft. For adjustment of barometric
draft controls, follow furnace or boiler manufacturer's recommendations for
over-fire draft setting.
AIR FILTER TEST—To obtain pressure drop across an air filter, follow pro-
cedure outlined above to determine static pressure on each side of the filter.
Subtract the smaller from the larger to get correct static pressure drop in
inches of water. Follow manufacturer's recommendations for filter cleaning
or replacement.
Copyright 2012 Dwyer Instruments, Inc. Printed in U.S.A. 7/12
• Air Meter
• White plastic ball
• Bottom plug
• Chemically treated
pipe stem cleaners
• Nylon bristles to clean
calibration orifice
• Case
• Supply grille probe
• 14˝ length 3/16˝ x
5/16˝ rubber tubing
• Angle connector
• Return grille probe
• Air velocity calculator
• Instructions (not shown)
Phone: 219/879-8000 Fax: 219/872-9057
www.dwyer-inst.com
DWYER INSTRUMENTS, INC.
P.O. Box 373 • MICHIGAN CITY, IN 46360 U.S.A.