Brand: Murphy

Murphy 20P / 25P Series Pressure Swichgage Gauge with Switch

Name: Murphy 20P/25P Pressure Swichgage Gauge – Datasheet & Quote
Brand: Murphy
SKU: 20P/25P Swichgage

Description

Engine pressure gauge with a built-in alarm or shutdown contact

The Murphy 20P / 25P Series Pressure Swichgage combines a diaphragm-actuated pressure gauge with an electrical switch in one housing. The 20 Series has a 2 inch (51 mm) dial and the 25 Series a 2-1/2 inch (64 mm) dial. The switch is used to trip an alarm or a shutdown device when the monitored pressure leaves its set band.

Enovation Controls designed the Swichgage to protect engines and equipment in oil field, marine, irrigation, construction and trucking service, typically on engine lube oil pressure, water pump pressure, hydraulic pressure and air pressure. Ranges run from 0-15 psi (103 kPa, 1.0 bar) up to 0-400 psi (2.8 MPa, 28 bar). The gauge is built in a coated steel case with a polycarbonate lens, a polished stainless steel bezel, a unitized diaphragm chamber and a removable pulsation dampener.

Technical specifications

Values are taken from Enovation Controls bulletin 94116 for the 20 and 25 Series.

Parameter	Specification
Dial sizes	20 Series: 2 in (51 mm); 25 Series: 2-1/2 in (64 mm)
Pressure ranges	0-15 psi (103 kPa) [1.0 bar] to 0-400 psi (2.8 MPa) [28 bar]
Maximum pressure	2 x scale up to 0-200 psi; 1-2/3 x scale for 0-300 psi; 1-1/4 x scale for 0-400 psi
Sensing element	Beryllium copper diaphragm
Process connection	1/8-27 NPTM, brass
Accuracy, ranges up to 300 psi	+/-3% of full scale in the lower quarter, +/-2% in the middle half, +/-3% in the upper quarter
Accuracy, 400 psi range	+/-3% lower quarter, +/-3% middle half, +/-5% upper quarter
Ambient / process temperature	-40 to 150 F (-40 to 66 C) / -40 to 250 F (-40 to 121 C)
Case, bezel, lens	Plated steel with mounting clamp (not on direct mount); polished stainless steel bezel; high-impact polycarbonate lens
Limit contact (20P, 25P)	SPST, pilot duty only, 2 A at 30 VAC/DC; normally closed when the low limit is met; gold flashed silver; leads 18 AWG x 12 in (305 mm)
Snap switch (20PE, 25PE)	SPDT, 3 A at 30 VDC inductive; 4 A at 125 VAC inductive; leads 20 AWG x 12 in
Weight	20 Series: 8 oz (0.23 kg); 25 Series: 11 oz (0.31 kg)
Dimensions	20 Series: 3 x 3 x 3 in (76 mm); 25 Series: 4-3/4 x 4-3/4 x 2-3/4 in (121 x 121 x 70 mm)

Base models and options in the bulletin

The bulletin lists five base models for each size. The 20P and 25P use the gauge pointer as one switch pole that touches an adjustable limit contact. The 20PE and 25PE (formerly 20EO and 25EO) have an internal snap-acting SPDT switch that sets on falling pressure and resets as pressure rises. The 20PABS and 25PABS add an SPDT snap switch for a pre-alarm. The 20P7 and 25P7 add a front, semi-automatic lockout that holds the pointer away from the contact during start-up and releases once pressure passes the set point. The 20PG and 25PG are MurphyGage versions without contacts.

Option codes include a black bezel (B1), direct mount (D), high and low contacts (HL), knob adjustment of the face contact (K), oil sealing with silicone oil (OS) and light pipe illumination for 12 VDC or 24 VDC on the 20 Series (IP1, IP2).

Choosing a range and protecting the contacts

Enovation Controls advises selecting the scale so that normal operating pressure sits in the middle half of the dial, where accuracy is best. The Swichgage contacts are for light-duty switching only. Inductive or high-current loads need a magnetic switch, and the bulletin points to the Tattletale magnetic switches for that purpose, with typical wiring diagrams shown.

Before ordering, confirm the base model, dial scale (psi/kPa or psi/bar), range, factory contact setting, process thread and whether the 12 in leads suit the panel. Enovation Controls lists this product family on its Legacy Products page, which describes those items as less popular or outdated but still available for purchase. Confirm current availability and any replacement part before ordering.

Documents and quotation

The attached Enovation Controls bulletin 94116 (revision dated 2019/04/11) is the source for every value above. Seven Star LLC supplies Murphy products as an independent supplier in Muscat and quotes against the part you specify. Send the model code, range, scale, options and quantity with your enquiry. Browse other pressure instrumentation for related items.

Datasheets & Documents

Datasheet Murphy 20 and 25 Series Pressure Swichgage bulletin 94116 (rev. 2019/04/11) Download

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About brand

Murphy is the engine and equipment instrumentation brand of Enovation Controls, LLC, headquartered in Tulsa, Oklahoma, USA. Enovation Controls operates as a stand-alone subsidiary of Helios Technologies, and the Murphy name goes back to 1939, when Frank W. "Pat" Murphy formed FW Murphy Manufacturing around a safety switch for engine protection. Seven Star LLC is an independent supplier in Muscat and lists selected Murphy products for engines, generator sets and pumps.

Murphy product groups

The classic Murphy range includes Swichgage and Murphygage pressure and temperature gauges, level switches, magnetic pickups, vibration switches, Tattletale annunciators and Sentinel battery chargers. Newer Murphy products include PowerCore controllers and PowerView displays with CAN J1939 communication. Enovation Controls lists many classic Murphy items on its Legacy Products page, which describes them as still available for purchase.

Ordering Murphy parts: what we need

Send the full model code, range or scale, thread, voltage and any options. Because many Murphy parts are legacy designs, we check the configuration and current availability against Enovation Controls documents before quoting.