TROUBLESHOOTING
SYMPTOMS
Pump runs, but no water delivered
Not enough water delivered
Not enough pressure
Excessive vibration
Abnormal Noise
Pump stops
Overheating
CAUSE
ELECTRICAL
A. No voltage in power system.
B. No voltage on one phase (Three Phase units).
C. Low voltage at motor.
D. Motor leads improperly grouped for voltage.
E. Control failure.
F. Thermal overload switch open
G. Installation failure.
H. Open windings.
I. Frequency variation.
MECHANICAL
A. Flow through pump completely or partially
obstructed.
B. Wrong direction of rotation.
C. Pump lost prime.
D. Internal leakage.
E. Loose parts
F. Stuffing box not properly adjusted
SYSTEM
A. Pressure required by system at design flow rate
exceeds pressure rating of pump.
B. Obstruction in suction piping
C. Pressure rating of pump exceeds pressure
requirement of system at design flow rate.
14
ELECTRICAL
A
B
C
D
E
F
X
X
X
X
X
X
X
X
X
X
X
X
X
Check phase-to-phase on line side of starter contactor.
Check phase voltage on line side of starter contactor. Isolate open circuit
Running voltage across each leg of motor must be ±10% of nominal voltage shown
Check control device, starter contactor, H-O-A selector switch, etc., for malfunction.
Check phase-to-phase on line side of starter contactor.
Check motor or windings to ground with megohmmeter.
Check frequency of power system. Must be less than 5% variation from motor
Locate and remove obstruction. Refer to repair instructions for disassembly.
Reverse rotation of three phase motor by interchanging any two leads.
See manufacturer's instructions for reversing single phase motor.
Check impeller for wear of controlled clearances (See Repair Instructions).
Compare pump pressure and flow rate against pump characteristic curve. Check for
closed or partially closed valve in discharge piping system.
Reduce system pressure requirement. Increase pressure capability of pump.
Compare pump pressure and flow rate against pump characteristic curve.
Inspect discharge piping system for breaks, leaks, open by-pass valves, etc.
If necessary, reduceflow rate by partially closing discharge valve.
PROBABLE CAUSE
G
H
I
A
B
X
X
X
X
X
Corrective Action
Check circuit breaker or fuses
(circuit breaker, fuse, broken connections, etc.)
on nameplate.
Refer to lead grouping diagram on motor nameplate.
Check leg-to-leg with ohmmeter.
nameplate rating.
Reprime. Inspect suction system for air leaks.
Inspect. Repair.
Adjust gland.
Locate and remove obstruction.
MECHANICAL
SYSTEM
C
D
E
F
A
X
X
X
X
X
X
X
S873 (08-01-20)
B
C
X
X
X
X
X
X
X
X