255-100 Analog Output Evaporation Gauge

The 255-100 Analog Output Evaporation Gauge is used to determine the evaporation rate by measuring the changing water level in an evaporation pan. A standard National Weather Service Class A Evaporation Pan is recommended. The sensor consists of a float, pulley, and counterweight attached to a precision 1000-ohm potentiometer mounted through a gear assembly in a weatherproof housing. The triangular base plate is equipped with three leveling screws. The potentiometer produces a resistance output proportional to the position of the float which can be monitored on site using a data logger or a strip chart recorder, or monitored remotely by telemetry equipment. The instrument can be placed directly in the pan, or connected to the pan using the 255-100P/F stainless steel pipe and fittings.


255-100 Evaporation Gauge
  Accuracy: 0.25%
  Rotation: Continuous
  Resistance: 1000 ohms
  Operating temperatures: -40° to 60° C
  Linearity: 0.25%
  Range: 0-10"
System accuracy: Evaporation gauge with pan and pipes ± 0.25% over 10" range
Float: 4" diameter
Height: 27-1/2"
Diameter: 8"
Base: 16" triangle with leveling screws
Water input port: 1/2" NP coupling, female
Cable: 3 conductor, 50' included
Weight/Shipping: 7-1/2 lbs/30 lbs
Shipping box: 15" x 15" x 30" (oversize)

255-100-P/F Stainless Steel Pipe & Fittings
Material: 304 stainless steel
Dimensions: 60" long, 1/2" NPT fitting
Weight/Shipping: 5 lbs/6 lbs

Ordering Information

255-100 Analog Output Evaporation Gauge
255-100P/F Stainless Steel Pipe and Fittings, 60"
255-100P/F-S Stainless Steel Pipe and Fittings, 6"
255-100POT Replacement Potentiometer

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