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Pump
Troubleshooting
4. Pump runs but does not pump
down the wet well.
a. On
three
phase
pump rotation may be wrong.
Wiring of pump to con trol
pan el
may
be
sequenced.
b. Impeller may be dragging
in volute due to sol ids.
High am per age draw would
identify this.
c. Refer to the pump manual for
other possibilities such as closed
discharge gate valve, etc.
5. Severe humming/chat ter ing of
contactors and control relays.
a. There may be low voltage.
Check voltage at primary
and secondary of control
transformer
volt me ter. This low voltage
condition may cause severe
chat ter ing and burnout of
contactors and relays.
b. Contactor may have dust
around
magnet
struc ture.
Dry
as re quired.
c. Check
voltage
control panel. Contactors
require
a
minimum
85% of full volt age to pull
in without chatter. If the
problem
is
a
one, measure voltage with
recorder on a 24 hour basis.
d. Make sure the floats are
locat ed away from any
turbu lence.
e. Dry out the junction box
(if
furnished);
in the junction box may
cause relays to energize
intermittent ly.
8
6. Short cycling pump.
a. Check float controls.
7. Run light stays on.
a. Selector switch may be in the
Hand position.
8. Nuisance
only,
over load on motor starters or
cir cuit break ers.
re verse
a. Check pump amp draw with
amp probe and compare to
nameplate amps on pump.
b. The impeller may be locked
up due to excessive debris or
solids.
c. Possible motor failure (fault in
windings).
d. Pump may be miswired to
ter mi nal block.
e. Voltage
unbalance.
only. Voltage un bal ance on
three phase power sources
us ing
a
can cause motor current to
become
exces sive
re sult.
over load
premature motor failures
can be expected if the
of
coil
current unbalance exceeds
or
clean
five percent.
to
the
Percent
Current
Unbalance
of
To determine if motor current
re cur ring
un bal ance is a function of the motor
or the power supply:
1. Label
ter mi nals 1, 2, and 3 respectively.
2. Record the amperage for each lead.
3. Move each lead to the next
moisture
terminal (1 to 2, 2 to 3,
3 to 1).
tripping
of
and
current
Three
phase
un bal anced
and
heating
will
Trip ping
of
the
protectors
and
Maximum Current
=
Difference from x 100
Average Current
_______________
Average Current
the
leads
and
the
4. Again read the amperage of
each lead.
5. Move each lead to the next terminal
(1 to 3, 2 to 1, 3 to 2).
6. Again read the amperage of
each lead.
7. If the unbalance moves with
the motor leads, the un balance
is caused by the mo tor. If
the unbalance remains with the
terminals, the un bal ance is in
the pow er supply.
8. If the current unbalance exceeds
five percent, nui sance tripping or
ex ces sive heating will result.
9. Connect leads for the lowest
percent of current un bal ance.
f. Connections
components. Single phase
only.
1. Disconnect all power from
the
panel
before
these checks.
2. Motor
winding
read ings.
a. Disconnect
all
motor leads from panel
terminal blocks.
b. Using a volt-ohmmeter, with
the scale set on RX1, measure
the resistance be tween the
leads with the chart.
Typical
Motor
Resistance
Winding
Leads
Reading
Main
Black to
White
Start
Black to
Red
(Middle)
Both
White to
Red
(Main & Start)
and
start
making
re sis tance
three
Lowest
Next
Lowest
Highest
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