Environmental Products
Model LS-800 HLI
High Level Indicator
Instruction Bulletin No. 155896
These Sensors may not be compatible with indicating
and alarm equipment supplied by other manufacturers
Note: LS-800 HLI sensors are non-voltage producing devices and do not contain energy storing com-
ponents. However, since primary use is in hazardous locations, an appropriate intrinsically safe inter-
face device is required.
Gems LS-800 HLI liquid level sensor operates on a direct,
simple principle. A float is equipped with powerful, permanent
magnets. As the float rises or lowers with liquid level, it actuates
a magnetic reed switch mounted within the stem. This condition
either opens or closes the electrical circuit to operate an exter-
nal alarm or control circuit. When mounted vertically, this basic
design provides a consistent accuracy of ±1/8th inch.
Sensor Operating Principle
Gems LS-800 HLI High Level Indicator has a 2" NPT mounting, making it ideal for use in underground and aboveground
storage tanks. When mounted vertically at the tank top, it reliably indicates high liquid level. This indicator is exceptionally
versatile. The unit adapts to just about any environment due to rugged construction and the multiple design options avail-
able. The LS-800 HLI is available in brass or stainless steel, making it suitable for use with a wide range of liquids.
Adjustable versions of the LS-800 HLI are available for varying tank sizes. A special cinch nut on the mounting allows the
stem to travel up or down, to fine-tune actuation points. The extent of the adjustment depends on the unit length and dis-
tance from the mounting to the highest float stop.
Note: Please refer to specific Gems outline drawings for
operational specifications.
Permanent
Magnet
Float
Hermetically
Sealed Magnetic
Reed Switch
N
S
Reed
Switch
Glass
Envelope
N
S
N
S
MAGNET
Adjustable
1-1/4"
Ref.
1-1/2"
Ref.
Liquid Tight
Fitting
2" NPT
1-5/16"
Ref.
1-1/2"
Ref.
1/2" NPT
Adjustment
Nut
2" NPT
Mounting Types
Float Types
Nitrile
316 Stainless Steel
1-13/16"
(46.0 mm)
1-7/8" Dia.
(47.6 mm)
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2"
(50.8 mm)
2-3/32"
(53.3 mm)
2-9/64"
(54.2 mm)
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Actuation Level
LO ± 1/16"
(Length
Overall)
L1 ± 1/8"
Actuation
Level
2" Min.
(63.5 mm)
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