User's Manual

PAGE 12 —ST2010 SERIES SUBMERSIBLE PUMP • OPERATION AND PARTS MANUAL — REV. #3 (12/07/12)
FLOAT SWITCHES
FLOAT SWITCH THEORY
Mercury monitoring is a mercury-switch actuated, liquid-
level control that has proven to be more economical
and longer lasting than other types of liquid-level control
systems, easily replacing and improving upon diaphragm
switches, air bubble systems and electro-mechanical
switches most often relied upon in the past.
HOW IT WORKS
There is a tilt-sensitive mercury switch hermetically sealed
within each float. As the liquid level (water) rises or falls,
the float changes its angle until the mercury switch makes
(closed, Figure 4) or breaks (open, Figure 5) the circuit.
Maximum pumping range is 120 degrees. See Figure 3
below.
Figure 3. Pumping Range (Float Switch)
PUMPING RANGE
The pumping range of the pump is determined by the float
switch tether cord. Use Table 3 as guide line to determine
your required pumping range. Pumping ranges are based
on non-turbulent conditions. Range may vary due to water
temperature and cord shape. Please note as the tether
length increases, so does the variance of the pumping
range.
DESIGN FEATURES
Constructed of rigid, durable ABS polymer ultrasonically
welded. The all-steel mercury switch is held by positioning
pins. Interior is filled with cell foam.
 Suitable for most liquid environments.
 Hermetically sealed.
 Thick-walled non-corrosive PVC plastic enclosure.
 Pressure tested to 60 ft. (18.2 meters).
 Mercury switch reliability, proven to 500,000 cycles.
 Standard SJO, 16-gauge, 2 conductor cord (20 ft./6.09 m).
Figure 4. Float Switch (Closed)
Figure 5. Float Switcfh (Open)
Table 3. Pumping Range
Tether Length
2 in.
5.08 cm.
4 in.
10.16 cm.
6 in.
15.24 cm.
8 in.
20.32 cm.
10 in.
25.4 cm.
12 in.
30.48 cm.
14 in.
35.56 cm.
16 in.
40.64 cm.
Pumping Range
6 in.
15.24 cm.
10 in.
25.4 cm.
14 in.
35.56 cm.
18 in.
45.72 cm.
22 in.
55.88 cm.
27 in.
68.58 cm.
31 in.
78.74 cm.
35 in.
88.9 cm.