Franklin Electric 2HP 20GPM 4400 Serie Manuel Du Propriétaire page 6

LOW-YIELDING WELL
A low-yielding well exists when the output from the pump
is greater than the yield of the well. It can reduce the
water level to the suction screen so that a mixture of air
and water enters the pump. Pumping may stop since the
pump cannot generate pressure with insufficient water.
In this case, the column of water already in the drop pipe
holds the check valve closed and an airlock may develop
inside the pump. Because the conditions ensure neither
adequate lubrication of the pump nor proper cooling
for the motor, damage can result if power is not cut off
quickly. Use one or more of the following methods to
correct and/or protect this installation.
1. Install additional length of drop pipe to place pump
lower in well if possible.
2. Install a Franklin Pumptec or similar electronic
drawdown sensor.
3. Install a floatless liquid level control. This device
consists of an electrical relay activated by currents
flowing through the ground-return circuits of
electrodes hung in the well. The lower (STOP)
electrode, just above the pump, ensures that the
water level can never be pumped down to the suction
screen. The upper (START) electrode, just below
the lowest static water level, ensures that the pump
can start again as soon as the well has recovered.
A floatless liquid level control works in series with
the pressure switch. Refer to the manufacturers
instructions provided with control.
4. Install a flow control valve in the discharge line
upstream from the pressure switch. This restricts
the output from the pump without affecting the rate
that water can be drawn from the pressure tank.
Nevertheless, a heavy demand for water could
empty the pressure tank, so a tank with a bonded
diaphragm, air cell, or water bag is recommended.
5. Install a smaller pump to avoid over pumping the well.
Have dealer size pump to the well yield.
6. Install a low-pressure cut-off switch. A low pressure
cut off switch, or a pressure switch with such an
arrangement built in, protects a shallow-well pump
from losing its prime, but it does not always provide
satisfactory protection to a submersible pump from
the effects of over pumping the well. This is because
it responds to a loss of pressure at the surface,
which may occur after an air lock has formed inside
the pump. We recommend either a floatless liquid
level control or a flow control valve, in that order,
in preference to a low-pressure cutoff switch as
protection against over pumping.
6
DISCHARGE PLUMBING
Fig. 1 illustrates a typical well installation showing above
ground components. Adhere to the following items when
installing the discharge plumbing.
1. Install an above ground check valve upstream from
the pressure switch.
2. Always install a pressure relief valve in the system.
The relief valve should be capable of discharging the
flow rate of the pump at the rated working pressure of
the pressure tank. Locate the relief valve close to the
pressure tank.
3. Install a pressure switch between the check valve and
the pressure tank. Refer to Fig. 2, 3, or 4 for proper
wiring connections of pressure switch.
4. Install a pressure tank as close as possible to
the pressure switch. Refer to manufacturer's
recommendations for installation.
TROUBLESHOOTING
1. PUMP FAILS TO START
a) Electrical trouble - call dealer or electrician.
b) Drawdown protection device has pump turned off.
c) Overload tripped.
d) Reset low pressure cutoff switch (if installed).
2. PUMP FAILS TO DELIVER WATER
a) Air lock in pump.
b) Clogged intake screen.
c) Insufficient well yield.
3. PUMP GIVES REDUCED OUTPUT
a) Insufficient well yield.
b) Worn pump.
c) Clogged intake screen.
d) Low voltage.
e) Incorrect rotation (3-phase only).
4. PUMP CYCLES TOO FREQUENTLY
a) Excessive pressure drop between pressure switch
and pressure tank.
b) "Cut-in" pressure at pressure tank too high.
c) "Cut-out" pressure at pressure tank too low.
d) Waterlogged pressure tank.
e) Start and stop electrodes of floatless liquid level
control set too close together.
f) Tank sized too small to meet system requirements.
5. OVERLOADS TRIP
a) Electrical trouble - call dealer or electrician.
6. PRESSURE SWITCH CYCLES RAPIDLY WHEN
PUMP STARTS
a) Pressure switch too far from pressure tank.
b) Adjust air charge of tank to manufacturer's
recommendations.