Dwyer A1F User Manual

Series A1F Compact OEM Pressure Switch

Specifications - Installation and Operating Instructions

A1F

A1F with A-447

Bulletin IN-92

INSULATIVE BARRIER

(OPEN ON TOP)

SPDT SNAP

SWITCH

SET POINT

ADJUSTMENT CAP

1/2 NPT
(MALE CONNECTION)

1/4 NPT
(FEMALE CONNECTION)

1-7/16

[36.51]

(3) ELECTRICAL

TERMINALS

GROUND

SCREW

3-3/4

[95.25]

ø1-53/64

[ø46.43]

The Series A1F Compact OEM Pressure Switch is ideal for

panel mounting wherever a high-quality, economical open-case or
weatherproof control is required.

INSTALLATION

1. Location: Select a location where the temperature limits of -40

to 180°F (-40 to 82°C) will not be exceeded. Locate the switch as
close as possible to the pressure source. Long lengths of piping
will not affect accuracy of the actuation point but will slightly add
to response time.

2. Mounting and Processing Connection: Avoid mounting sur-

faces with excess vibration which could cause false actuation
when pressure is near setpoint. The switch should be mounted
within 20° of vertical for proper operation. Mount the switch by
connecting it to the process piping using either 1/4˝ NPT female
or 1/2˝ male connection. Pipe joint compound or TFE thread tape
should be used to prevent leakage.

3. Electrical Connections: The SPDT snap switch includes nor-

mally open, normally closed and common connections. The com­mon and normally open contacts will close and the common and
normally closed contacts will open when pressure increases to the
setpoint. The actions will reverse when pressure decreases below
the setpoint minus the deadband. A green grounding screw is
provided on the switch bracket. All wiring should be in accor­dance with local codes.

SETPOINT ADJUSTMENT

1. Determine the setpoint pressure. The approximate actuation
point can be set by turning the adjustment cap up or down, align­ing the top of the O-ring, located above the cap, with the appro­priate scale graduation.

2. Connect tubing or piping from the pressure port on bottom of
switch to one leg of a tee. Connect the second leg to a pressure

4

5-7/16

[138.11]

1-29/32

[48.41]

1-1/2

[38.10]

4-11/16

[119.06]

[101.6]

1-17/32

[38.89]

3-1/16

[77.79]

SPECIFICA T IONS
Service: Compatible liquids and gases.
Wetted Materials:

Pressure Chamber: 316 SS.

Diaphragm: Fluorocarbon.
Temperature Limit: -40 to 175°F (-40 to 80°C).
Pressure Limits: 750 psig (51 bar).
Enclosure Rating: No rating for open construction. Installed

properly within an optional A-447 enclosure meets NEMA 4X
standards.

Switch Type: SPDT snap switch.
Electrical Rating: 15A @ 120/240/480 VAC, 1/8 HP @ 125

VAC, 1/4 HP @ 250 VAC.

Electrical Connection: Screw terminals.
Process Connection: 1/4˝ female NPT and 1/2˝ male NPT.
Mounting Orientation: Within 20° of vertical.
Set Point Adjustment: Knurled screw cap with indicating scale.
Deadband: Fixed, See deadband chart.
Weight: 10.5 oz (297 g).

test gage of known accuracy and in an appropriate range. The
third leg should be connected to a controllable source of pressure.

3. Connect a volt/ohm meter or other circuit tester to the snap
action terminals to indicate when switching occurs.

4. Slowly apply pressure to the system and note the pressure at
which switching occurs.

5. Operate the switch through several cycles to confirm proper
actuation point.

6. Remove test apparatus and attach switch to pressure source
and control circuit wiring. Place switch in service.

DWYER INSTRUMENTS, INC.

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

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

Example of how to order:

- O - SS - 1 - 4

A1F

1 2 3 4 5

1. Diaphragm Designation:

F - Fluorocarbon

2. Enclosure Designation:

O - Open Construction No Enclosure

3. Housing Material Designation:

SS - 316SS

4. Switch Designation:

1 - SPDT Snap Action Switch

5. Operating Pressure Range Designation:

1 - 2 to 15 psig

2 - 4 to 75 psig

3 - 8 to 225 psig

4 - 16 to 450 psig

Series A1F Deadband Chart-psig (bar)

Deadband at

Range

2 to 15 (0.14 to 1.03)

4 to 75 (0.28 to 5.17)

8 to 225 (0.55 to 15.5)

16 to 450 (1.1 to 31.0)

Minimum Range

2 (0.14)

4 (0.27)

8 (0.55)

15 (1.0)

Deadband at
Maximum Range

3 (0.21)

15 (1.0)

25 (1.7)

50 (3.5)

MAINTENANCE

Upon final installation of the Series A1F Compact OEM Pressure Switch,

no routine maintenance is required. A periodic check of the system cali-

bration is recommended. The Series A1F is not field serviceable and

should be returned if repair is needed (field repair should not be attempted

and may void warranty). Be sure to include a brief description of the prob-

lem plus any relevant application notes. Contact customer service to

receive a return goods authorization number before shipping.

©Copyright 2008 Dwyer Instruments, Inc. Printed in U.S.A. 7/08 FR# 89-440838-10 Rev.2

DWYER INSTRUMENTS, INC.

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

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