GENERAL
BEFORE INSTALLING, CHECK THE SENSOR MODEL SELECTED
FOR COMPATIBILITY TO THE PROCESS MEDIA IN CONTACT
WITH THE SENSOR AND WETTED PARTS.
J21K Differential Pressure Switch utilizes opposing metal bellows to detect
pressure differences between two pressure sources. The bellows are
connected to a mechanical linkage. When the pressure at the high port
exceeds the pressure at the low port by a pre-determined amount, the
mechanism operates a snap-action electrical switch. The predetermined
actuation pressure can be adjusted by the user as described below.
Part I - Installation
Tools Needed
- Adjustable wrenches (2)
- Flat blade screwdriver
MOUNTING
INSTALL UNIT WHERE SHOCK, VIBRATION AND TEMPERATURE
FLUCTUATIONS ARE MINIMAL. MOUNT UNIT SO THAT
MOISTURE IS PREVENTED FROM ENTERING THE ENCLOSURE.
DO NOT MOUNT UNIT IN AMBIENT TEMPERATURES EXCEEDING
PUBLISHED LIMITS.
Surface mount in any position via two mounting ears. Never turn this unit
by grasping enclosure. Always hold a wrench on the bellows housing (or
fitting) when connecting pressure joints.
WIRING
DISCONNECT ALL SUPPLY CIRCUITS BEFORE WIRING UNIT.
WIRE UNITS ACCORDING TO NATIONAL AND LOCAL
ELECTRICAL CODES. MAXIMUM RECOMMENDED WIRE SIZE
IS 14 AWG.
ELECTRICAL RATINGS STATED IN LITERATURE AND ON
NAMEPLATES MUST NOT BE EXCEEDED, OVERLOAD ON A
SWITCH CAN CAUSE FAILURE ON THE FIRST CYCLE.
Remove the two (2) screws retaining the cover and gasket. Remove cover.
Connect conduit to the enclosure using a conduit fitting that is suitable for
your installation. A watertight conduit fitting (option M900 or equivalent)
must be used for NEMA 4 protection. Wire directly to the switch terminals
in accordance with local and national electrical codes. Bring the wires up to
the terminals from the rear of the enclosure to prevent interference with the
mechanism.
Part II - Adjustments
Tools Needed
- 5/16" open end wrench
For set point adjustment and re-calibration, connect the unit to a calibrated
pressure source.
Set point adjustment is achieved by varying the gap between the mechanical
actuator and the plunger on the electrical switch
J21K
To raise the differential pressure setting, turn the 5/16" hex head screw out
(to the left).
To lower the differential pressure setting, turn the 5/16" hex head screw in
(to the right).
IMJ21K-01
Differential Pressure Switch
Type J21K
UNITED ELECTRIC
CONTROLS
Installation and Maintenance
Instructions
Please read all instructional literature carefully and thoroughly before starting. Refer to the final page for the listing of Recommended Practices, Liabilities
and Warranties.
