Issue Date: March 11, 2011

Preferred Utilities Manufacturing Corporation

TG-EL-D4A Fuel Sentry Control Unit, PLS-1 Non-Discriminating Sensor for Reservoirs



Output type


Sampling frequency


Operating principle

reed switch/float


Test Results:

PLS Liquid Level Switch (Reservoirs)

unleaded gasoline



Detection time (sec)




Fall time (sec)




Lower detection limit (in)





Control panel:
  Six intrinsically safe sensor inputs can be used for level indication and/or leak detection.

Provides audible and visual alarms.

Sensor:   Primarily designed for use with diesel fuel and other distillates but can be used with other fluids - see manufacturer for specific limitations.

*This evaluation determined the sensors' responses to the liquids shown above.  Biodiesel blends B6-B20 meeting ASTM D7467 and biodiesel B100 meeting ASTM D6751 would also produce an alarm if the sensor threshold is exceeded.  Responses to these fuels were not determined, but would be expected to be very similar to the diesel responses.

Provides up to six independent liquid level switches on one sealed probe up to 72 inches length.

May be used with any clean, low viscosity, non adhering fluid compatible with brass, solder, epoxy and Buna-N.

Used on fuel oil day tanks to control the addition of oil from remote pumps and alarm at high and low levels.

Can also be used for detection of leaks into sumps or other containment vessels used to collect liquids containment pipeline leaks or other types of sump.


Preferred Utilitites Manufacturing Corporation

Evaluator:  Ken Wilcox Associates

31-35 South Street

Tel:  (816) 443-2494

Danbury, CT 06810

Date of Evaluation:  06/17/10

Tel:  (203) 743-6741



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