Dwyer A2 User Manual

Important Points!

A2 Pressure Switches

Product must be maintained and installed in strict accordance
with the National Electrical Code and Dwyer product catalog
and instruction bulletin. Failure to observe this warning could
result in serious injuries or damages.

For hazardous area applications involving such things as (but
not limited to) ignitable mixtures, combustible dust and
flammable materials, use an appropriate explosion-proof
enclosure or intrinsically safe interface device.

The pressure and temperature limitations shown on the
individual catalog pages and drawings for the specified flow
switches must not be exceeded. These pressures and
temperatures take into consideration possible system surge
pressures/temperatures and their frequencies.

Selection of materials for compatibility with the media is critical
to the life and operation of Dwyer products. Take care in the
proper selection of materials of construction, particularly wetted
materials.

Life expectancy of switch contacts varies with applications.
Contact Dwyer if life cycle testing is required.

Ambient temperature changes do affect switch set points,
since the specific gravity of a liquid can vary with temperature.

Dwyer Products have been designed to resist shock and
vibration; however, shock and vibration should be minimized.

Filter liquid media containing particulate and/or debris to
ensure the proper operation of our products.

Electrical entries and mounting points in an enclosed tank
may require liquid/vapor sealing.

Dwyer Products must not be field-repaired.

Instruction Bulletin No. 2041 17

Installation

T o inst all the switches, use a suitable wrench on the port and plumb
into place with the proper sealant. For electrical wiring, refer to
wiring codes on the next page and to the specification sheet for the
switch ratings. For low DC loads (<50 mA, TTL logic) use switches
with gold contacts. All the switches are adjustable unless they were
ordered with the IP68 submersible option, in which case they are
factory set and not field adjustable. All switches are maintenance­free.

Adjusting the Set point

1) Using a 1/8 inch Allen (Hex) wrench, adjust clockwise to
increase the set point and counterclockwise to lower the set

point. (Adjustments are done while applying a known pres­sure and monitoring the switch’s state.)
2 ) After verifying the set point re-assemble the switch.

Physical damage sustained by the product may render it
unserviceable.

DWYER INSTRUMENTS,INC.

P.O.BOX 373 MICHIGAN CITY, INDIANA 46361, U.S.A.

Phone: [phone]
Fax: [phone]
Lit-By Fax: [phone]
www.dwyer-inst.com
e-mail: [e-mail]

Dimensions

Specifications

Process T emperature -4°F to +250°F (-20°C to +120°C)
Ambient Temperature -40°F to +250°F (-40°C to +120°C)
Switch SPST, 100 VA, 42V max. (>2 million

cycles @ 1,000 psi, max. 200 cycles/min.)

Approvals CE
Repeatability 5% of Highest Set Point @ 70°F (20°C)
Wetted Parts
Diaphragm Kapton®
Fitting Brass
Electrical Termination 6.3mm (1/4”) Sp ade or Screw Terminals
Process Fitting G or NPT 1/4”(optional 1/8”)
Deadband 1-2 psi
Proof Pressure 500 psi (34.5 bar)

Weight, Approximate 0.14 lbs. (0.06 kg)

Submersible Option

1.95”
(50)

1.12”
(29)

1/8 ALLEN WRENCH
ADJUSTMENT SCREW

.054”
(14)

15/16” A.F.

(24) 1.67”

.35”

(9)

(42.5)

.35”

(9)

∅.82”

(∅21)

SEE
ORDERING
INFORMATION

HEX 15/16”

(24)

.35”

(9)

∅.82”

(∅21)

SEE
ORDERING
INFORMATION

The pressure switch is designed and manufactured in accordance
with Sound Engineering Practice as defined by the Pressure
Equipment Directive 97/23/EC. This pressure switch must not be
used as a “safety accessory” as defined by the Pressure Equipment,
Article 1, Paragraph 2.1.3.

The CE Mark on the unit does not relate to the Pressure Equipment
Directive.

Maintenance/Repair

Regular maintenance of the total system is recommended to assure sus­tained optimum performance. These devices are not field repairable and should
be returned to the factory if recalibration or other service is required. Af ter first
obtaining a Returned Goods Authorization (RGA) number, send the unit freight
prepaid to the following. Please include a clear description of the problem
plus any application information available.

Dwyer Instruments, Inc.
Attn: Repair Department
102 Highway 212

Michigan City , IN 46360