120 Series Temperature & Pressure Switches

Rugged, Explosion-proof Pressure, Vacuum, Differential Pressure and Temperature Switches



As safety requirements become more stringent, the determining factor in specifying an industrial pressure, differential pressure and/or temperature switch rests upon that switch protecting equipment, processes and personnel. Meeting hazardous location requirements through worldwide approvals and certifications, UE’s 120 Series is the choice where potentially explosive or highly corrosive atmospheres exist.


The 120 Series offers a variety of pressure, vacuum, differential pressure and temperature ranges, as well as process connections, wetted materials and sensor types. With a common flexible platform, models can quickly be adapted at the factory for special requirements, such as ranges, process connections and electrical ratings. Typical industries using 120 Series switches include chemical, petrochemical, refinery, oil and gas production and transmission, and pharmaceuticals.





Product Overview




Class 1, Divisions 1 & 2, Zone 1

UL listed, cUL certified, ATEX flame-proof & CE (LVD, PED) compliant; other worldwide hazardous location approvals


Dual electrical conduit openings provide mounting flexibility while terminal block provides ease of wiring

SPDT, DPDT, or dual SPDT switch output

  of pressure sensor materials, including welded stainless steel diaphragms and bellows

Internal or external set-point adjustment

Heat trace & freeze protection temperature models

Adjustable set-point ranges:

         Pressure & Vacuum: 30 ”Hg Vac to 6000 psi

             1 to 413,7 bar

         Water Column: 300 “wc Vac to 250 “wc

              -746,7 to 622,3 mbar

        Differential Pressure: 0.2 “wcd to 500 psid

              0,5 mbar to 34,5 bar

        Temperature: -180 to 650 ºF

              -117.8 to 343.3 ºC





  Standard product approvals include cULus, ATEX & IECEx

  Optional approvals for Russia, Ukraine and China

  Internal adjustment hex or external adjustment via calibrated dial(s)

   with tamper resistant cover

  Integral cover lock

SPDT, DPDT or dual SPDT output

  Wide variety of sensor materials

  Optional Hastelloy® and Monel® sensor material for corrosive media

  Wide adjustable deadband models

  Flush mount sensors

  Heat tracing temperature models

  Most models available for immediate delivery!



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


Ambient Temperature                   -58 to 160°F (-50 to 71°C); models 36-39, 520-525, 540-548, 701-705, 15834-15839:

    Limits                                          0 to 160°F (-17 to 71°C); types 820E, 822E: -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;

                                                          less than 2% for types E121& E122


Set point                                       Temperature models: Type B, C and F: ±1% of full scale range

     Repeatability                              Type E: ±2% of full scale range

                                                          Pressure models 126-164, S126B-S164B, 171-174, 270-274, 358-376, 520-535,

                                                          540- 543, 560-564, 701-705, 15622, 15834,-15839: ±1% of full scale range; models

                                                          450-559: ±1/2% of full scale range; models 36-39, 183-194, 483-494, 544-548,

                                                          565-567, 612-680, 15875: ±1-1/2% 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; coverlock; internal set point lock

                                                          standard on types J, C, F; gasketed stainless steel tamper-resistant dial cover on types

                                                          B, H, E; aluminum nameplate


Enclosure Classification             Certified to enclosure type 4X. Class I, Division 1 product meets enclosure type 7;

                                                         Class  II, Division 1 product meets enclosure type 9. Certified to IP66 requirements


Switch output                               One or two SPDT; dual switch may be separated up to 100% of range; except type 822E

                                                         where switch #2 can be set up to 25% of range span below switch #1 setpoint; switches

                                                         may be wired “normally open” or “normally closed”. Two SPDT hermetic sealed

                                                         switches available on H122P models


Electrical rating                            15A 125/250/480 VAC resistive (standard) except types J120-15622, 15834-15839,

                                                         H121-15875: 20A 125/250/480 VAC resistive; H122P; 11A 125/250 VAC resistive;

                                                         B121-13272, B122-13322, E121-13273, E122-13321; 22A 480VAC resistive. Electrical

                                                         switches have limited DC capabilities. Consult factory for additional information


Reference Scales                         Types B, E & H: external dial. Scale divisions vary with range (see model charts)


Weight                                           3-8 lbs. Varies with type and model


Electrical  Connection                 Type H, B, E; one 3/4" NPT E/C; type J, C, F, 820E, 822E; two 3/4" NPT E/C;

                                                          terminal block standard


Pressure Connection                   Models S126B-S164B, 171-194, 483-494, 520-535: 1/2" NPT (female); models

                                                         560-564: 2"  flush mount connection; models 565-567: 1-1 ⁄ 2" flush mount connection;

                                                         models 540-548: 1/8" NPT (female); all others: 1/4" NPT (female)


Temperature Assembly                Bulb and capillary: 6 feet 304 stainless steel (standard) except for E121-13273 and

                                                         E122-13321: 10 feet; Immersion stem: nickel-plated brass (standard) except for

                                                         B121- 3272 and B122-13322: stainless steel. Fill: Model 1BS: solvent filled; models

                                                         2BS-8BS: non-toxic oil filled


Temperature Deadband               Type F120, 820E, 822E: typically 1%; type B-, C-, and E- 121 and 122: typically 2% of

                                                         range under laboratory conditions (70°F [21°C] ambient circulating bath at rate of

                                                         1/2°F per minute change)


Pressure Deadband                     Type F120, 820E, 822E: typically 1%; type B-, C-, and E- 121 and 122: typically 2% of

                                                         range under laboratory conditions (70°F [21°C] ambient circulating bath at rate of

                                                         1/2°F per minute change)


Differential Pressure                    Differential pressure indication available types H121K and H122K with option M210

    Indicator Option M210               (check model availability under options); accuracy approximately 1% mid 50% of range,

                                                         3% at ends; window is plexiglass and gasketed; indicator may be field adjusted for

                                                         approximately ±1% accuracy at any set point within range


  Temperature Indication              Temperature indication available types 820E and 822E. Indication accuracy is ±1% of

                                                         adjustable range


home / products / hazardous location / 120 series

Tel:  (617) 926-1000

Fax: (617) 926-4354

Do you have a  customer service or technical question?  Please email us and we will get back to you.

180 Dexter Avenue, Watertown, MA  02472-4200