
ECONOMICAL PRESSURE 
AND VACUUM SWITCHES
PSW-620/PSW-630 Series
Vacuum to 500 psi 
Starts at
$
80
⻬ External Pressure Scale 
and Pointer for Easy 
Setpoint Adjustment
⻬ Silver Switch Contacts
Rated for 5 A @ 250 Vac 
or 3 A @ 28 Vdc
⻬ 1 A Gold-Plated Contacts
for TTL or Dry Contacts 
SPECIFICATIONS
Process Temp: -55 to 105°C
(-65 to 221°F); 2% setpoint shift can 
occur below -23°C (-10°F) or above 
52°C (125°F)
Repeatability: ±2% of max system 
pressure
Cycling: Not to exceed 20 cycles/min 
Warranty: 3 year/1 million cycles 
Proof Pressure: 150% max pressure 
Wetted Parts: 17-7 PH stainless steel,
loctite sealing compound #271, 
ZA8 chromate finish
Enclosure: Zinc alloy, chromate finish 
Dimensions: 48 L x 28 mm Dia.
(1.9 x 1.1")
Pressure Port: 
Electrical Connection: 300 mm (12")
pigtail leads, 20 AWG, polyvinyl 
insulated
Wiring Code (Pressure):
Red = N/C 
White = N/O 
Black = Common
Wiring Code (Vacuum):
Red = N/O 
White = N/C 
Black = Common
Weight: Approx. 57 g (2 oz)
1
/8-27 MNPT
To Order (Specify Model Number)
MODEL NO. PRICE 
Gage Pressure Switches (Units = psi )
PSW-621 $85 0.8 to 28.5 1.6 to 30 0.8 to 1.3 30 1 A 
PSW-622 85 2.0 to 38.3 3.0 to 40 1.0 to 1.7 50 1 A 
PSW-623 85 3.0 to 96.5 4.5 to 100 1.5 to 3.5 100 1 A 
PSW-624 85 7.5 to 242.5 9.7 to 250 2.2 to 9.0 250 1 A 
PSW-625 85 15 to 485 20 to 500 5.0 to 21 500 1 A 
PSW-631 80 0.8 to 28.5 1.6 to 30 0.8 to 1.3 30 5 A 
PSW-623 80 2.0 to 38.3 3.0 to 40 1.0 to 1.7 50 5 A 
PSW-633 80 3.0 to 96.5 4.5 to 100 1.5 to 3.5 100 5 A 
PSW-634 80 7.5 to 242.5 9.7 to 250 2.2 to 9.0 250 5 A 
PSW-635 80 15 to 485 20 to 500 5.0 to 21 500 5 A
Vacuum Switches (Units = inHg Vacuum )
PSW-626 $85 1.6 to 27.0 2.7 to 28.2 1.3 to 2.7 1 A 
PSW-627 85 4.0 to 24.8 5.1 to 28.2 1.5 to 3.2 1 A 
PSW-628 85 6.0 to 21.5 8.4 to 28.2 2.0 to 7.3 1 A 
PSW-636 80 1.6 to 27.0 2.7 to 28.2 1.3 to 2.7 5 A 
PSW-637 80 4.0 to 24.8 5.1 to 28.2 1.5 to 3.2 5 A 
PSW-638 80 6.0 to 21.5 8.4 to 28.2 2.0 to 7.3 5 A
*
Comes complete with operator’s manual. 
Ordering Example: PSW-635, switch for maximum system pressure of 500 psig with
5 A switch contact, $80.
Field 
Adjustable
Knurled 
locking
ring.
PSW-631, $80.
See switch
accessories on page
Both models shown actual size.
PSW-633, $80.
H-37 for audible alarms 
and relay modules.
MOST POPULAR MODELS HIGHLIGHTED!
ADJUSTABLE RANGE
Exceeding these values may cause a shift in the setpoint.
Recommended Reference Book: 
EE-2685, $40. Visit omega.com/bobi for Additional Books
H-13
Newnes Dictionary of Electronics,
DEADBAND
MAX
28.2 inHg
vacuumor
0 psig
*
*
Sliding 
Gage 
pointer.
SWITCHDECREASING INCREASING PRES

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