Omega Products PSW20A User Manual

COMPACT, RUGGED, ADJUSTABLE
PRESSURE AND VACUUM SWITCHES

PSW21 Series
PSW22 Series

U Adjustable Setpoint

1

U

⁄8 NPT or Center Spout

for

U Pressure and Vacuum Models Available
U UL Recognized, CSA Certified Up to 25 A

1

⁄8 ID Tubing

These compact pressure and vacuum switches are designed
and manufactured to exacting standards to meet the needs
of OEM manufacturers and instrument makers for a low-cost,
stable, repeatable switch. Plastic mechanisms and housings
are acetal to minimize moisture absorption and maintain
dimensional stability. Plastic welding is accomplished using
advanced microprocessor-controlled, ultrasonic welding
equipment. All switches are 100% tested at high and low settings
and at the proof pressure. Units are delivered with the setpoint
at approximately the midpoint of the adjustable range.

SPECIFICATIONS

Approval: UL-recognized,

CSA-certified switches; microswitches
bear the CE and ENEC mark

Temperature Range: -10 to 70°C
(14 to 158°F)

Setpoint Accuracy:

±10% of setting at 21°C (70°F)

Note: Pressure settings may change over the
temperature range.

Hysteresis (Deadband):

15 to 25% of the setpoint
Electrical: See table (page H-8) for

the switch amp rating, 250 Vac
Terminals: 6.35 mm (0.25") standard

“slide-on” male

Materials of Construction

Body and Mechanism: Acetal

Diaphragm: EPDM

(ethylene-propylene diene monomer)

Screws: Stainless or zinc-plated steel
Springs: Stainless steel
Media Compatibility: Air, water and

many other fluids and gases that are
compatible with EPDM and acetal

Note: Mineral oil and similar fluids are not
compatible with EPDM. Request nitrile
diaphragm (see “Custom Switches” on
next page).

Weight: 50 g (1.8 oz)
Overall Dimensions: Approx

54 x 76 x 45 mm (2.125 x 3 x 1.75")

PSW22(*)D

Shown larger
than actual size.

PSW21(*)

Setting: The pressure switch is field

adjustable using the hex head set screw
at the center of the pressure switch
(PSW 21/22-WRENCH). The vacuum
switch is field adjustable using the
Phillips head screw on the switch carrier.

Dual Pressure Switch: The DPDT
(2 switches) will both change state at
approximately the same setpoint. On
DPDT units, one switch may be set
to lead or lag the other (see “Custom
Switches” on next page).

To Order

PRESSURE SWITCHES PSW21,
MODEL NO. ADJUSTABLE RANGE PROOF PRESSURE SPDT SWITCH RATING

PSW21A 3 to 7 inH2O 20 psig 3 A (resistive)
PSW21B 5 to 35 inH2O 20 psig 5 A (resistive)
PSW21C 1 to 6 psig 50 psig 21 A (resistive)
PSW21D 4 to 11 psig 50 psig 25 A (resistive)
PSW21E 9 to 18 psig 50 psig 25 A (resistive)
PSW21F 15 to 28 psig 50 psig 25 A (resistive)
PSW21G 25 to 40 psig 200 psig 25 A (resistive)
PSW21H 35 to 65 psig 200 psig 25 A (resistive)
PSW21J 50 to 100 psig 200 psig 25 A (resistive)
PSW21K 75 to 120 psig 200 psig 25 A (resistive)

Visit omega.com/psw21_psw22 for Pricing and Details

1

⁄

8 MNPT with

9

⁄

16 Threaded Mounting Nut Included

H-7

ADJUSTABLE PRESSURE AND VACUUM SWITCHES

PSW21(*)D

PSW22(*)

All products shown
smaller than actual size.

ACCESSORIES

PSW21/22-WRENCH

Allen wrench for adjusting
pressure switches only, $1;

vacuum switch is adjusted
with a Phillips head screwdriver

CUSTOM SWITCHES

Custom pressure switches are
available–50 piece minimum
order; consult Pressure
Engineering for price and
delivery

Custom Options:

Factory setting available
at specified setpoint

Switch Body: Noryl
Diaphragm: Nitrile
DPDT: Switch can be factory set

so that each switch operates at
a different pressure setting.

®

PRESSURE SWITCHES PSW21

1

⁄

8 MNPT with

9

⁄

16 Threaded Mounting Nut Included

ADJUSTABLE PROOF DPDT SWITCH
MODEL NO. RANGE PRESSURE RATING

PSW21BD 10 to 35 inH

O 250 inH2O 5 A (resistive)

2

PSW21CD 1 to 6 psig 50 psig 21 A (resistive)
PSW21DD 4 to 11 psig 50 psig 25 A (resistive)
PSW21ED 9 to 18 psig 50 psig 25 A (resistive)
PSW21FD 15 to 28 psig 50 psig 25 A (resistive)
PSW21GD 25 to 40 psig 200 psig 25 A (resistive)
PSW21HD 35 to 65 psig 200 psig 25 A (resistive)
PSW21JD 50 to 100 psig 200 psig 25 A (resistive)
PSW21KD 75 to 120 psig 200 psig 25 A (resistive)

1

PRESSURE SWITCHES PSW22 Center Spout for

⁄

8

ID tubing with

9

⁄

16

Threaded Mounting Nut & Tube Lock Nut Included

ADJUSTABLE PROOF SPDT SWITCH
MODEL NO. RANGE PRESSURE RATING

PSW22A 3 to 7 inH2O 250 inH2O 3 A (resistive)
PSW22B 5 to 35 inH2O 250 inH2O 5 A (resistive)
PSW22C 1 to 6 psig 50 psig 21 A (resistive)
PSW22D 4 to 11 psig 50 psig 25 A (resistive)
PSW22E 9 to 18 psig 50 psig 25 A (resistive)
PSW22F 15 to 28 psig 50 psig 25 A (resistive)

1

PRESSURE SWITCHES PSW22 Center Spout for

ADJUSTABLE PROOF DPDT SWITCH

⁄

8

ID tubing with

9

⁄

16

Threaded Mounting Nut & Tube Lock Nut Included

MODEL NO. RANGE PRESSURE RATING

PSW22BD 10 to 35 inH2O 250 inH2O 5 A (resistive)
PSW22CD 1 to 6 psig 50 psig 21 A (resistive)
PSW22DD 4 to 11 psig 50 psig 25 A (resistive)
PSW22ED 9 to 18 psig 50 psig 25 A (resistive)
PSW22FD 15 to 28 psig 50 psig 25 A (resistive)

VACUUM SWITCHES PSW21

ADJUSTABLE PROOF SPDT SWITCH

1

⁄

8 MNPT with

9

⁄

16

Threaded Mounting Nut Included

MODEL NO. RANGE PRESSURE RATING

PSW21L 3 to 7 inWC Vac 350 inWC Vac 3 A (resistive)
PSW21M 6 to 16 inWC Vac 350 inWC Vac 10 A (resistive)
PSW21N 13 to 25 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21P 20 to 40 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21Q 35 to 80 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21R 75 to 150 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21T 145 to 300 inWC Vac 350 inWC Vac 21 A (resistive)

VACUUM SWITCHES PSW21

ADJUSTABLE PROOF DPDT SWITCH

1

NPT with

⁄

8

9

Threaded Mounting Nut Included

⁄

16

MODEL NO. RANGE PRESSURE RATING

PSW21MD 6 to 16 inWC Vac 350 inWC Vac 10 A (resistive)
PSW21ND 13 to 25 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21PD 20 to 40 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21QD 35 to 80 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21RD 75 to 150 inWC Vac 350 inWC Vac 21 A (resistive)
PSW21TD 145 to 300 inWC Vac 350 inWC Vac 21 A (resistive)

Ordering Example: PSW21D, adjustable pressure switch for setpoints between 4 and 11 psig, with 25 A
SPDT switch.

PRESSURE SWITCHES

H

H-8

PRESSURE, VACUUM, AND
DIFFERENTIAL SWITCHES

PRINTED CIRCUIT BOARD MOUNTABLE

PSW23 Series
PSW24 Series
PSW25 Series

U UL Recognized,
CSA Certified

U Printed Circuit
Board Mountable

U Leads Available
as an Option

U Several Fitting Styles

Available

U Pressure, Vacuum,
and Differential
Models Available

U Fixed Setpoint

PSW23-(*)

All products
shown larger
than actual size.

PSW25-(*)

PSW24-(*)

These miniature single-pole
switches are used in pressure
and vacuum applications in which
moderate accuracy is sufficient.
The fixed setpoint is factory set.

SPECIFICATIONS

Temperature Range:

-10 to 75°C (14 to 167°F)

Setpoint Accuracy:

±10% of setting at 21°C (70°F)

Note: Pressure settings may change
over the temperature range.

Materials of Construction

Lower Body: Rynite plastic (with pin

terminals molded in)

Upper Body: Acetal plastic
Diaphragm: EPDM (ethylene-propylene

diene monomer)

Internal Parts: Acetal plastic
Screws: Stainless steel or zinc-plated

steel, flash
Contacts: SPST (normally open); gold

flash over silver-plated copper alloy
Pins: Gold flash over silver-plated

copper alloy
Leads [Optional (-L)]: 8", 20 AWG

stranded PVC-insulated wire fastened to
the switch terminals

Electrical: SPST (NO), 1 A resistive
250 Vac; ratings are dependent on
actuation pressure and must be derated
at lower pressures (under 1 psi).

Pressure Connection

PSW23: 1⁄8 MNPT
PSW24: Center spout for 1⁄8 ID tubing;

provided with 9⁄16-18 mounting nut.

PSW25: Radial spout for 1⁄8 ID tubing
Proof Pressure: See table
Hysteresis (Deadband): Negligible
Media Compatibility: Air, water and

many other fluids and gases that are
compatible with EPDM acetal plastic

To Order

PRESSURE MODELS PSW23

MODEL NO. FIXED SETPOINT PROOF PRESSURE

PSW23-10W 10 inH2O 250 inH2O
PSW23-20W 20 inH2O 250 inH2O
PSW23-1P 1 psig 40 psig
PSW23-2P 2 psig 40 psig
PSW23-10P 10 psig 40 psig
PSW23-20P 20 psig 40 psig
PSW23-30P 30 psig 60 psig

Ordering Example: PSW23-10P, fixed setpoint of 10 psig.

Visit omega.com/psw21_psw22 for Pricing and Details

1

⁄8 MNPT with 9⁄16 Threaded Mounting Nut Included

H-9

Note: Mineral oil and similar fluids are not
compatible with EPDM. Request nitrile
diaphragms (see “Custom Switches” on next
page). Contacts are exposed to media on
base spout.

Overall Dimensions:

38 x 25 mm (1.5 x 1")

Pin Spacing: 12.7 mm (0.5") centers
Weight: 6 g (0.2 oz)
Approvals: UL-recognized,

CSA-certified switches