PSW-180 SERIES
Differential Pressure Switches
INSTRUCTION
S H E E T
M-1477/0500
NEVER TIGHTEN BY TURNING THE
CONTROL INTO THE FITTING.
MODELS PSW-181, 182, 185, 186 HAVE
A POLYSULPONE PORT WITH 1/4” NPSF
THREAD. A 1/4 NPT OR 1/4 NPS
FITTING MAY BE USED WITH THIS
CONNECTION. HOWEVER, IN BOTH CASES, THE
MATING FITTING WILL BOTTOM-OUT IN THE
PRESSURE CONNECTION. THEREFORE, WITH
THESE MODELS, TEFLON TAPE MUST BE
APPLIED TO FITTING FOR A TIGHT SEAL. DO
NOT OVER TIGHTEN. CONNECTION TORQUE
MUST NOT EXCEED 2 FT. / LBS. OVER
TIGHTENING MAY DAMAGE THE PORT.
WIRING
ALL LIVE SUPPLY CIRCUITS MUST BE
DISCONNECTED BEFORE WIRING THE
CONTROL. FOR ENCLOSED UNITS,
CONNECT THE CONDUIT TO THE HOLE IN
ACCORDANCE WITH NATIONAL AND LOCAL
CODES. BRING WIRES UP TO THE TERMINALS
FROM THE REAR. MAXIMUM RECOMMENDED
WIRE SIZE IS 16 AWG.
Unscrew terminal just enough to put stripped
wire under terminal block clamp.
Tools Needed
Screwdriver
Use screwdriver to turn external adjusting screw
on the side. Turn “in” (clockwise) to increase
pressure setting. For best setting accuracy, set the
switch using the actual working pressures
encountered in the application.
GENERAL
The PSW-180 differential pressure switch utilizes
dual diaphragm sensors to monitor the difference
in pressure between two sources.
Tools Needed
Screwdriver to accommodate
customer-supplied mounting screws
Adjustable wrenches (2)
MOUNTING
LOCATE SWITCH WHERE VIBRATION,
SHOCK, AND AMBIENT TEMPERATURE
FLUCTUATIONS ARE MINIMAL. TO
AVOID DAMAGE TO CONTROL, ALWAYS HOLD
THE WRENCH ON THE WRENCH FLATS OR HEX
PORTION OF THE PRESSURE CONNECTION
WHEN TIGHTENING.
The control can be mounted in any position. Locate
where ambient temperature is above 30°F and
below 160°F.
Surface Mounting
Insert two #6 screws through mounting ear holes
on 2” centers (Recommended mounting for
maximum vibration resistance).
Pipe Mounting
Mount unit from its por t(s). Always hold a
wrench on pressure port when making pressure
connection.
Making Pressure Connection
Use a wrench on the pressure port and thread a
1/4” NPTM fitting into the por t. Be sure to
connect high pressure source to port labeled
“HIGH”. Similarly, connect low pressure source
to “LOW”.
Part I - Installation
Part II - Adjustments
Dimensions
MODEL
PORT
DIM A.
DIFFERENTIAL
PRESSURE
PSW-181, 182,
1/4” NPSF
185, 186
Polysulphone
2.75” (69.9 mm)
PSW-183,
184, 187, 188
1/4” NPTF Brass
3.125” (79.4 mm)
