A20 / A25P Series Pressure Swichgage®

The A20 Series (2 inch/51 mm dial) and the A25 Series (2-1/2 inch/64 mm dial) Swichgage models are diaphragm-actuated, temperature-indicating gages, with built-in electrical switches for tripping alarms and/ or shutdown devices. Ranges are available from 32°-120° F (0°-45° C) through 300°-440° F (160°-220° C).

Swichgage® instruments are built in the USA and have protected engines and equipment in applications such as oil and gas, marine, irrigation, construction and trucking applications to monitor engine coolant, crankcase oil, transmission oil and others for more than 80 years.

Base Models Specifications Downloads How To Order

These rugged, built-to-last instruments are face sealed from the environment by the unique combination of a polycarbonate case and lens, a polished stainless steel bezel and O-ring seals. Ranges above 30 psi (207 kPa) [2 bar] are sealed from the external environment (except PE Series). Ranges of 30 psi and lower have a small weep hole in the bottom of the case. Accuracy and protection from moderate overpressure is assured by a unique, unitized diaphragm chamber. A built-in pulsation dampener helps eliminate pointer flutter and is removable for cleaning.

A20P and A25P Series Swichgage
The gage pointer makes with an adjustable limit contact to complete a pilot duty circuit. Contacts have self-cleaning motion to ensure electrical continuity.

A20PE (was A20EO) and A25PE (was A25EO) Swichgage
Features internal snap-acting SPDT switches, instead of the single pole/pointer contacts, for three wire control and can be wired to make or to break a circuit. When the switch closes on falling pressure, it becomes set, as pressure rises the switch resets (refer to wiring diagram).

  • Model A25PE is CSA listed for non-hazardous areas.
  • Model A25PE-EX is CSA listed for Class I, Division 1, Groups C and D hazardous areas.

A20PABS and A25PABS Swichgage instrument
Same as A20P and A25P with internal SPDT snapswitch for pre-alarm

A20PG and A25PG MurphyGage instrument
Gauge-only model without switch contact(s).

  • Dial: White on black, dual USA/UK standard scale (U.S.A. standard scale is psi/kPa; U.K. standard scale is psi/bar)
  • Case: Polycarbonate/glass filled, corrosion-resistant; steel mounting clamp included
  • Bezel: Polished stainless steel, standard; others available
  • Lens: Polycarbonate, high-impact
  • Pointer: Tempered nickel silver
  • Oil: Silicon oil
  • Ambient Temperature Range: -40°F (-40°C) thru 150°F (66°C)
  • Process Connection: 1/8-27 NPTM brass.
  • Sensing Element: Beryllium copper diaphragm.
  • Gage Accuracy: See bulletin in downloads
  • Maximum Pressure: See bulletin​​​ in downloads
  • Adjustable Limit Contact (A20P and A25P): SPST contact; pilot-duty only, 2A@30 VAC/DC; Closed when the low limit is met. Open when pointer is in normal operating range. Contacts are gold flashed silver.
    • Limit Contact Adjustment: by a 1/16 in. hex wrench through 100% of the scale.
    • Wiring: A20P: Number 4 screw terminals; A25P: Number 6 screw terminals
  • Snap-Switch Rating SPDT, 3 A@ 30 VDC inductive; 4 A @ 125 VAC inductive
    • Wiring: A20PE: Number 4 screw terminals; A25PE: Number 6 screw terminals
  • Unit Weight: A20 Series: 8 oz. (0.23 kg); A25 Series Models: 11 oz. (0.31 kg).
  • Unit Dimensions: A20 Series: 8 oz. (0.23 kg); A25 Series Models: 11 oz. (0.31 kg).

 WARNING: This product may expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information about California Propsition 65, go to www.P65Warnings.ca.gov or visit our California Proposition 65 page.

  • A20 / A25P Series Technical Sales Bulletin (94030)
    • Includes:
      • Dimension Diagrams
      • Pressure Ranges and Factory Settings
      • Features of the A20 / A25 Series
      • Using A20 / A25 Series instruments with a Magnetic Switch
      • Pre-Alarm Using A20/A25PABS
      • Typical Internal Wiring Diagrams

Additional product documentation can be found on our product support website or by clicking the Help Center button above.

Part Number Description Notes
05702176 A20 Series Clamp Lite Assembly; 12V Illumination — Order Separately
05702177 A20 Series Clamp Lite Assembly; 24V Illumination — Order Separately

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