Float Switches - MULTIQUIP ST2037F Operation And Parts Manual

FLOAT SWITCH THEORY
The float switch allows the pump to start and stop
automatically when a prefixed liquid (water) level has been
reached. A multiple closure device makes it highly reliable.
This is the most universally-used float switch in the world
for the automation of pumps.
HOW IT WORKS
This float switch is an economical chamber design float-
type, liquid level switch that uses a microswitch for switching
operation. As the liquid level (water) rises or falls, the float
changes its angle until the microswitch makes or breaks
the pump. The maximum switch angle range is 90 degrees.
See Figure 3 below.
Figure 3. Switch Angle Range
DESIGN FEATURES
The float switch employs a microswitch and a latching
ball for the switching operation. The latching ball design
provides excellent resistance to nuisance trips due to fluid
turbulence. The case and cable are hermetically sealed via
re-injection molding.
„ Suitable for most liquid environments.
„ Hermetically sealed.
„ Thick-walled non-corrosive Polypropylene enclosure.
„ Max depth level, 1bar
„ Micro witch mechanical life - 10,000,000 operations
PAGE 12 — ST2037F/2040TF SUBMERSIBLE PUMP • OPERATION AND PARTS MANUAL — REV. #3 (12/14/17)
PUMPING RANGE
The pumping range of the pump is determined by the float
switch tether cord. The length of the float switch tether code
is set to 150 mm at the factory. Please set the tether length
to within 150 mm to prevent an improper operation.
Refer to Figure 4 for the pumping range of the ST2037F
and ST2040TF. The minimum submergence level should
never be less than 150 mm for the ST2037F or 160 mm
for the ST2040TF above the pump bottom.
Pumping ranges are based on non-turbulent conditions.
Range may vary due to water temperature and cord shape.
45°
90°
45°
Figure 4. Pumping Range (Float Switch)

FLOAT SWITCHES

ST2037F
PUMP
ON
PUMP
OFF
ST2040TF
PUMP
ON
PUMP
OFF