Differential Pressure Switch - J21K Series


The J21K differential pressure switch monitors the difference between two system pressures or vacuums and senses excessive flow deviation, or verifies that a filter is clogged.


The J21K's rugged design - with epoxy coated enclosure and sealed metal bellows - lends itself to exacting applications.  Widely used in refrigeration (chiller) and compressor applications, the J21K can be used for filter status monitoring and proof of flow.

Product Overview




  Rugged, NEMA 4X, epoxy coated enclosure

  SPDT switch output

  Welded 316 stainless steel or brass sensors

  Unique isolated sensor design

  Adjustable ranges:

       • 30 "Hg Vac to 90 psid

       • 1 bar Vac to 6,2 bar d

  UL listed and cUL certified

  Optional ATEX or GOST intrinsic safety compliance

  Designed to meet Enclosure Type 4X

  SPDT switch output

  Adjustable deadband option for precise on-off control

  Brass or welded stainless steel bellows sensors

  External manual reset option




Designed to meet Enclosure Type 4X (with

   watertight conduit fitting)

UL listed and cUL certified

Optional ATEX and Rostechnadzor (GOST-R)

   intrinsic safety compliance

Optional adjustable deadband

Single switch output

Opposing bellows design




Storage Temperature                 -65 to 160°F (-54 to 71°C)

Ambient Temperature                -40 to 160°F (-40 to 71°C); set point typically shifts less than 1% of range for

   Limits                                          a 50°F (28°C) ambient temperature change

Set point                                     ±1% of full scale range


Shock                                          Set point repeats after 15 G, 10 millisecond duration

Vibration                                      Set point repeats after 2.5 G, 5-500 Hz

Enclosure                                    Die cast aluminum, epoxy powder coated, gasketed

Enclosure Classification            Designed to meet enclosure type 4X requirements with M900 option

                                                         (watertight conduit fitting)

Switch output                              One SPDT snap action switch; switch may be wired "normally open" or

                                                         "normally closed"

Electrical rating                           15 A 125/250/480 VAC resistive. Electrical switches have limited DC

                                                         capabilities. Consult factory for additional information


Weight                                          Approximately 2 lbs. (0.90 kg.)

Electrical  Connection                7/8" diameter conduit hole

Pressure Connection                  Models 127-150, 232-254, 357, 16020: 1/4" NPT (female); models

                                                         S127B-S150B, 16021: 1/2" NPT (female)






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Tel:  (617) 926-1000

Fax: (617) 926-4354

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180 Dexter Avenue, Watertown, MA  02472-4200