11
Eng
lish (US
)
chapter discard.fm Page 11 Tuesday, June 7, 2011 9:29 PM
Possible causes
1. No power at motor.
2. Fuses are blown or circuit
breakers are tripped.
3. Motor starter overloads
are burned or have tripped
out.
4. Starter does not energize.
5. Defective controls.
6. Motor is defective.
7. Defective capacitor (single-
phase motors)
8. Pump is bound.
1. Wrong rotation.
2. Pump is not primed or is air
bound.
3. Strainer, check valve, or
foot valve is clogged.
4. Suction lift is too large.
5. Suction and/or discharge
piping leaks.
6. Pump is worn.
7. Pump impeller or connec-
tion port is clogged.
How to check
Check for voltage at motor
terminal box.
Turn off power and remove
fuses. Check for continuity
with ohm meter.
Check for voltage on line and
load side of starter.
Energize control circuit and
check for voltage at the hold-
ing coil.
Check all safety and pressure
switches for operation. Inspect
contact in control devices.
Turn off power and disconnect
wiring. Measure the lead to
lead resistances with the ohm
meter (R x 1). Measure lead to
ground values with ohm meter
(R x 100K). Record measured
values.
Turn off power and discharge
capacitor. Check with ohm
meter (R x 100K).
Turn off power and manually
rotate pump shaft.
Check wiring for proper con-
nections.
Turn pump off, close isolation
valve(s), and remove the prim-
ing plug. Check fluid level.
Remove strainer, screen or
valve and inspect.
Install compound pressure
gauge at the suction side of
the pump. Start pump and
compare reading to perform-
ance data.
Pump runs backwards when
turned off. Air in suction pipe.
Install pressure gauge, start
pump, gradually close the dis-
charge valve and read pressure
at shut-off.
Disassemble and inspect pump
passageways.
Fault
A. Pump does not run.
B. Pump runs but at reduced
capacity or does not deliver
water.
Troubleshooting Chart
How to fix
If no voltage at motor, check
feeder panel for tripped cir-
cuits and reset circuit.
Replace blown fuses or reset
circuit breaker. If new fuses
blow or circuit breaker trips,
the
electical
installation,
motor, and wires must be
checked.
Replace burned heaters or
reset. Inspect starter for other
damage. If heater trips again,
check the supply voltage and
starter holding coil.
If no voltage, check control
circuit fuses. If voltage, check
holding coil for shorts. Replace
bad coil.
Replace worn or defective parts
or controls.
If an open or grounded wind-
ing is found, remove the motor
and repair or replace.
When the meter is connected
to the capacitor, the needle
should jump towards “0”
ohms and slowly drift back to
infinity. Replace capacitor if
defective.
If shaft does not rotate eas-
ily, check coupling setting and
adjust as necessary. If shaft
rotation is still tight, remove
pump and inspect. Disassem-
ble and repair.
Correct wiring.
Refill the pump, replace the
plug, and start the pump. Long
suction lines must be filled
before starting the pump.
Clean and replace. Reprime
the pump.
Reduce suction lift by lowering
the pump, increasing the suc-
tion line size, or removing high
friction loss devices.
Suction pipe, valves, and fit-
tings must be airtight. Repair
any leaks and retighten all
loose fittings.
Convert PSI to feet (Measured
PSI x 2.31 ft. / PSI = ____ft.)
Refer to the specific pump
curve for shut-off head for that
pump model. If head is close
to curve, pump is probably
OK. If not, remove pump and
inspect.
Remove any foreign materials
found.