Coolant or Oil Temperature

A20 and A25 Series Temperature SWICHGAGE®

AT-95026B

Revised 08-05

Catalog Section 10

A20T Series shown

2 and 2-1/2 in. (51 and 64 mm) Dial

■Corrosion Resistant Polycarbonate Case

■Indicating Gage and Limit Switch

■Switch Can Activate Alarms and/or Shut Down Equipment

■Critical/High Temperature Limit Switch Is Visible and Adjustable (Most Models)

■Contact(s) Isolated From Ground

Description

The A20 Series (2 inch/51 mm dial) and the A25 Series (2-1/2 inch/64 mm dial) SWICHGAGE® mod- els 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) thru 300-440°F (160-220°C).

All models of these rugged, built-to-last instruments are fully sealed from the environment by the unique combination of a polycarbonate case and lens, a pol- ished stainless steel bezel, and O-ring seals.

These vapor/pressure actuated gages feature a sealed capillary tube and a sensing bulb. When subjected to heat, the liquid in the sensing bulb changes to vapor creating pressure against a diaphragm mechanism.

The diaphragm translates this vapor pressure into a mechanical gage reading.

For series A20T and A25T, the gage pointer acts as a temperature indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contact(s) are isolated from ground. They have self-cleaning motion to enhance electrical continuity. Models A20TE and A25TE have internal snap-acting SPDT switches.

Gage-only models, without contacts (MURPHYGAGE®) are also available.

Applications

Applications for A20 and A25 Series temperature SWICHGAGE® instruments include: engines and equipment in Oil Field, Marine, Irrigation, Construction and Trucking industries. Monitoring Engine Coolant temperature, Crankcase Oil, Transmission Oil.

Specifications

Dial: White on black; U.S.A. standard scale is dual scale °F/°C; others available.

Case: Glass filled/Polycarbonate, corrosion-resis- tant; steel mounting clamp included. Bezel: Polished stainless steel, standard; others

are available.

Pointer: Tempered nickel silver; red tip.

Lens: Polycarbonate, high-impact.

Sensing Element: Beryllium copper diaphragm.

Capillary: PVC armored copper; 4 ft. (1.2 m)*. Stainless steel armor optional.

Sensing Bulb: Copper*.

Gage Accuracy: See accuracy chart, on page 2.

Maximum Temperature: See Temperature Ranges and Factory Settings table on page 2.

Adjustable Limit Contact (A20T and A25T):

SPST contact; pilot-duty only, 2 A @ 30 VAC/ VDC; isolated from case ground. Normally Closed when the high limit is met. Normally Open when pointer is in normal operating range. Contacts are gold flashed silver.

Limit Contact Adjustment: by a 1/16 in. hex wrench thru 100% of the scale.

Wiring: A20T: Number 4 screw terminals; A25T: Number 6 screw terminals.

Snap-Switch Rating (A20TE and A25TE):

SPDT, 3 A@ 30 VDC inductive; 4 A @ 125 VAC inductive.

Wiring: A20TE: Number 4 screw terminals; A25TE: Number 6 screw terminals.

Unit Weight: A20 Series: 11.9 oz. (0.370 kg). A25 Series Models: 13.3 oz. (0.413 kg).

Unit Dimensions: A20 Series: 4-3/4 x 4-3/4 x 3 in. (121 x 121 x 76 mm). A25 Series Models: 4-3/4 x 4-3/4 x 2-3/4 in. (121 x 121 x 70 mm).

Base Models

A20T and A25T Series SWICHGAGE® For these models the gage pointer makes with an adjustable contact to complete a pilot-duty circuit.

A20TL and A25TL SWICHGAGE®

For use on Ford Worldwide engines. Supplied with special sensing bulb.

A20TE and A25TE SWICHGAGE®

A20TE (was A20ESR) and A25TE (was A25ESR). Models with internal SPDT snap-switches, instead of the single pole/pointer contact(s). When the switch closes on rising temperature, it becomes Set. As temperature decreases the switch Resets. Model A25TE is CSA listed for non-hazardous areas. Model

A25TE-EX is CSA listed for Class I, Division 1, Groups

C & D hazardous areas.

A20TABS and A25TABS SWICHGAGE® Same as 20 and 25T with internal SPDT snap- switch for pre-alarm.

Cylinder Head Temperature

A20TH and A25TH SWICHGAGE® A20TH (was A20TL8133) and A25TH (was A25TL8133). For use on Air Cooled engines.

Gage–Only Models

A20TG and A25TG MURPHYGAGE®

Gage without contact(s).

*For optional capillary lengths, engine adapters, sensing bulbs and range combinations, see Murphy bulletin T-8428B.

**Products covered by this bulletin comply with EMC Council directive 89/336/EEC regarding electromagnetic compatibility except as noted.

Bulletin AT-95026B page 1 of 4

A25 Series, A20 Series specifications

The Murphy A20 Series and A25 Series are two advanced engine control and monitoring systems designed to optimize performance and enhance the productivity of various applications. Both series are recognized for their robust construction, user-friendly interfaces, and comprehensive functionalities, making them ideal choices for demanding industrial environments.

The A20 Series is particularly notable for its affordability and flexibility. This system is engineered to integrate seamlessly with various engine types and monitoring setups. It features a lightweight design, making it perfect for applications where space is a premium. Key characteristics include customizable screens, allowing operators to configure display parameters according to specific needs. The A20 Series is equipped with a wide range of sensors that monitor critical engine functions like oil pressure, temperature, fuel level, and engine RPM. With advanced alarm capabilities, it enables users to respond promptly to potential issues, thus safeguarding the engine and prolonging its operational lifespan.

On the other hand, the Murphy A25 Series offers enhanced capabilities tailored for more complex applications. It boasts a more extensive display, providing a clearer interface for monitoring multiple parameters simultaneously. The A25 Series also supports robust data logging features, which are invaluable for maintenance and analysis purposes. Users can access historical data to identify trends and troubleshoot issues effectively. The A25's built-in communication protocols allow for easy integration with existing control systems, thereby enhancing flexibility and ease of use.

Both series incorporate cutting-edge technologies to improve reliability and performance. Engineered with high-quality materials and advanced electronics, they operate effectively in challenging environments. These systems are designed to function in varying temperatures and humidity levels, ensuring consistent performance under fluctuating conditions.

In conclusion, the Murphy A20 and A25 Series represent a significant advancement in engine monitoring technology. While the A20 Series is ideal for simpler applications requiring flexibility and ease of use, the A25 Series caters to those needing advanced monitoring and data logging capabilities. Together, these systems provide powerful tools for enhancing engine efficiency, safety, and operational longevity, making them essential components in modern industrial applications. Whether for construction, agriculture, or other heavy-duty landscapes, Murphy's innovative solutions stand out for their reliability and performance.