Dwyer Instruments 477A Operating Manual

Bulletin D-26

Series 477A Handheld Digital Manometer

Specifications - Installation and Operation Instructions

SPECIFICATIONS

Service: Air and compatible gases.
Wetted Parts: Consult factory.
Accuracy: ±0.10% of full scale from 60 to 78°F

(15.6 to 25.6°C); ±1% of full scale from 32 to 60
and 78 to 104°F (0 to 15 .6 and 25.6 to 40°C).

Pressure Hysteresis: ±0.1% of full scale.
Pressure Limits: See chart.
Temperature Limits: 32 to 104°F (0 to 40°C).
Storage Temperature Limits: -4 to 176°F (-20

to 80°C).

Display: 4-digit LCD (.425˝ H x .234˝ W digits).
Resolution: See chart.
Power Requirements: 9 volt alkaline battery.

Battery included but not connected.

Weight: 10.2 oz. (289 g).
Connections: Two barbed connections for use

with 1/8˝ (3.18 mm) or 3/16˝ (4.76 mm) I.D. tubing
for 477A-1, 477A-2, 477A-3, 477A-4 and 477A-5
only. Two compression fittings for use with 1/8˝
(3.18 mm) I.D. x 1/4˝ (6.35 mm) O.D. tubing for
477A-6 and 477A-7 only.

Series 477A Digital Manometers are ver­satile, hand-held, battery operated manome­ters available in several basic ranges from 0­20 in. w.c. up to 100 psi. All models measure
either positive, negative or differential pres­sures with ±0.10% of full scale accuracy. You
can select from up to seven common English
and metric pressure units so conversions are
not necessary. A memory function allows
storage of up to 40 readings for later recall
and a backlight provides auxiliary lighting for
hard-to-see locations. Also standard are a
hold feature plus both visual and audible over­pressure alarms.

Model

Number

English

Range

Metric
Range

477A-1 0-20.00 in. w.c. 0-4.982 kPa
477A-2 0-40.00 in. w.c. 0-9.96 kPa
477A-3 0-200.0 in. w.c. 0-49.82 kPa
477A-4 0-10.00 psi 0-68.95 kPa
477A-5 0-30.00 psi 0-206.9 kPa
477A-6 0-50.00 psi 0-344.8 kPa
477A-7 0-100.0 psi 0-689.5 kPa

Maximum Pressure

477A-1 3 psi (0.21 bar)
477A-2 3 psi (0.21 bar)
477A-3 15 psi (1.03 bar)
477A-4 30 psi (2.07 bar)
477A-5 60 psi (4.13 bar)
477A-6 100 psi (6.89 bar)
477A-7 200 psi (13.78 bar)

Available Pressure Units:

477A-1 & 477A-2: psi, in. w.c., mm w.c., in.
Hg, mm Hg, Pa, kPa, bar, mbar

477A-3 & 477A-4: psi, in. w.c., mm w.c., in.
Hg, mm Hg, kPa, bar, mbar

477A-5, 477A-6 & 477A-7: psi, in. w.c., in.
Hg, mm Hg, kPa, bar, mbar

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

INSTRUCTIONS
Battery Installation

The unit is shipped with a separate 9 volt alkaline battery which must be installed before
operation. Remove the two screws holding the bottom endcap in place and remove the
endcap. Connect the battery to the enclosed battery clip observing correct polarity. Be
careful not to trap wires between the battery, case or foam pads which retain the battery.
This could make it difficult to install the battery or remove it later for replacement. Be sure
the rubber gasket is properly seated in the gasket channel of the endcap and replace end­cap. Note that the endcap will only fit one way because the holes are slightly off-center.
Place the “Z” shaped wrist strap clip in one of the screw recesses and replace the screws.
Do not overtighten the screws. Attach wrist strap to clip.

When battery replacement becomes necessary, use only a 9 volt alkaline type such as
a Duracell
duty are not recommended because of the increased potential for leakage. Alkaline batter­ies are also a better value because they last up to three times longer in this device.

®

MN1604, Eveready®522 or equivalent. Zinc-carbon types, often labeled Heavy-

On-Off Operation

The on-off control is a toggle function. Press and release the ON/OFF key once to turn
unit on; again to turn it off. If the manometer is left on with no activity for approximately 20
minutes, unit will turn itself off to conserve the battery.

Display Backlight

The Model 477A includes a display backlight to allow use in the dark or in poor lighting con­ditions. Manometer must be switched off before this feature can be activated. Next, press and
hold the ON/OFF key down. After about 1 second the backlight will come on and remain light­ed for approximately 2 minutes after which it will turn itself off to conserve battery life.

Zeroing Pressure Reading

Potential inaccuracy due to temperature effects can be minimized by re-zeroing immediately
before use. To zero the display, vent both ports to atmosphere so no pressure is applied to
either port. Press the ZERO/STORE key and - - - - will be momentarily displayed as zeroing
occurs. Zeroing is not possible when the memory mode is in use. It must be done before select­ing that function.

If the unit is accidently zeroed with pressure applied to one of the ports, the pressure read­ing might display incorrectly. To correct, vent the pressure ports to atmosphere and press the
ZERO/STORE key to zero the unit.

Pressure Connections

To measure single positive pressure, connect tubing to port marked + and vent oppo­site port to atmosphere. To measure differential positive pressure, connect higher positive
pressure to port marked + and lower positive pressure to port marked -. Manometer will
indicate the difference between the two.

Selecting Pressure Units

Up to seven pressure units are available. The display will indicate the current selection.
To change to different units, use the UNITS/LOC key. Each touch will cause an advance to
the next choice. The selected units will remain in memory even when power is shut off. This
way, your preference will always be displayed after the initial selection.