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ABLE are United Electric’s Exclusive Representative for Sales and Service in the UK and Ireland and can assist you and your customers in the following areas:

  • Application expertise
  • Our factory trained engineers offer after sales support, service and maintenance (contracts available)
  • Offer advanced United Electric pressure / temperature switch product training, either in-person or via video call.

Further to the above, ABLE can offer custom solutions based on your individual requirements. Email us now at [email protected]

United Electric J21K Series Differential Pressure Switch

ABLE Instruments are United Electric’s Exclusive Representative for Sales and Service in the UK and Ireland, including the UE J21K Series, for alarm, safety and emergency shutdown applications requiring a higher switch sensitivity. It monitors the disparity between process pressures or vacuum using sealed, opposing bellows sensors. Typical applications that utilize the J21K Series include proof of flow, filter monitoring, vacuum pumps, chillers, and compressors.

The UE J21K monitors the difference between two system pressures or vacuums, senses excessive flow deviation, or verifies that a filter is clogged. The J21K’s differential pressure switches’ rugged design lends itself to exacting applications. Widely used in refrigeration and compressor applications, the J21K can be used for filter status monitoring and proof of flow. A welded bellows sensor provides leak-free protection with precise on-off control through adjustable deadband option The United Electric J21K Series achieves application versatility through a variety of ranges and microswitches.


  • Rugged, NEMA 4x, epoxy coated enclosure
  • Sealed metal bellows sensors
  • SPDT switch output
  • Welded 316 stainless steel or brass sensors
  • Optional ATEX and Rostechnadzor (GOST-R) intrinsic safety compliance
  • Adjustable Ranges: 30 “Hg Vac to 90 psid (-1 bar Vac to 6,2 bar)
  • UL listed and cUL certified
  • Unique isolated sensor design

Have a particular application / project in mind? We’d welcome a call on +44 (0) 1189 169 420, or email us now at [email protected]

J21K Series Specifications:

Ambient Temperature Limits
-40 to 160°F (-40 to 71°C); Set point typically shifts less than 1% of range for a 50°F (28°C) ambient temperature change
Set Point Repeatability
±1% of full scale range
Set point repeats after 15 G, 10 millisecond duration
Set point repeats after 2.5 G, 5-500 Hz
Die cast aluminium, 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 ABLE for additional information.
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)
United States / Canada
UL Listed, cUL Certified
UL 508; CSA C22.2, no. 14 File # E42272
Low Voltage Directive (LVD) 73/23/EC & 93/68/EEC
Compliant to LVD
Products rated lower than 50 VAC and 75 VDC are outside the scope of the LVD
Pressure Equipment Directive (PED) 97/23/EC
Compliant to PED
Products rated lower than 7.5 psi are outside the scope of the PED
ATEX Directive (94/9/EC)
II 1G Ex ia IIC T6 Ga (OPTIONAL – code M405)
-50°C ≤ Tamb ≤ +60°C
UL International DEMKO A/S (N.B.#0539)
Certificate # DEMKO II ATEX 1105261X
EN 60079-0, 60079-11, 60079-26
Rostechnadzor Permit and GOST-R CoC (OPTIONAL – code M406)
Tamb = -50C to +60C
NANIO CCVE Certification Center
Certificate # ROSS US.GB05.Bo2933
GOST R 51330.0, 51330.1, 51330.10 & 51330.14
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Price: POA Contact 247ABLE