SPL Series - Mechanical Temperature Gauges

The 4-1/2 in. (114 mm) size dial gauge is a mechanical gauge for temperature indication. It is a combination indicating gauge and critical temperature limit switch. High and low temperature limit contacts are visible.

• Combination indicating gauge and critical temperature limit switches
• High and low temperature limit contacts are visible and adjustable
• Panel and wall mount versions available
• Typical Applications: Gas compressors, heaters and coolers, water pump temperature, engine coolant temperature and process temperature

The SPL Series includes adjustable, electrical contacts that can be used for start and stop, to trip alarms and to shut down equipment.

Panel and wall-mount versions are available as well as latching control relay versions.

Ranges are available from 15° to 250° F (9° to 121° C) through 130° to 350° F (54° to 177° C).

Basic Models
SPLC Series gauge: Surface-mount version of the gauge. For this model, the gauge pointer makes with two adjustable contacts to complete a pilot-duty circuit.

SPLFC Series gauge: Panel-mounting (round case) version of the SPLC

FW Murphy offers square case configurations altered to fit round panel openings, see Dimensions.

Basic Operation
This vapor-actuated gauge features a sealed capillary tube and sensing bulb. When subjected to heat, the liquid in the sensing bulb expands to vapor creating pressure against a bourdon tube mechanism. The bourdon tube translates this vapor pressure into a mechanical gauge reading.

For models SPLC and SPLFC, the gauge pointer acts as a pressure indicator and as one switch pole, which completes a circuit when it touches the adjustable limit contacts. Contacts have self-cleaning motion to ensure electrical continuity. A toggle switch is provided on SPLC models to override the low contact for equipment start-up.

SPecification

• Dial: White on black, dual scale, ° F and ° C standard, 4-1/2 in. (114 mm) diameter
• Case: Die-cast aluminum, surface or panel mount
• Capillary: PVC-armored copper tube, 5 ft. long (1.5 m) standard – (5, 10, 15, 20, 25 or 30 ft. long options)
• Sensing Bulb:
  • Copper bulb: 1/2 in. (13 mm) OD
  • Length: 7 in. (178 mm)
  • Minimum bulb insertion – see corresponding chart in sales bulletin
  • Pressure Rating: 600 psi (4.1 MPa) [41 bar]. Connection: 1/2 NPT compression fitting
• Overrange: Do not exceed 10% above full range
• Limit Contacts (SPLC and SPLFC): 1-SPDT, center off; pilot-duty; 2 A @ 30 V / 0.1 A @ 125 VAC. Contacts are gold-plated silver.
• Dry Relay Contact (BP Models): 10 A @ 28 VDC or 10 A @ 120 VAC
• Wire Connections:
  • Surface-mount models: 1/2 NPT conduit and terminal block
  • Panel mount models: Wire leads, 18 AWG (1.0 mm²) x 9 in. (229 mm) long
  • OS models: 1/2 NPT conduit and wire leads, 18 AWG (1.0 mm²) x 9 in. (229 mm) long
• Approximate Item Weight:
  • 8 lb. (3.6 kg)
  • Explosion-proof models: 22 lb. (10 kg)
• Item Dimensions:
  • 16 x 11 x 5-1/2 in. (406 x 279 x 140 mm)
  • Explosion-proof models: 12 x 12 x 9 in. (305 x 305 x 229 mm)