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9. Troubleshooting Chart
Difficulty
Probable Cause
Remedy
Pump does not
start
Coupling disconnected
Connect coupling
Faulty power source
Check power source
Blown fuse, and circuit breaker
Replace - eliminate overload
Broken wire
Locate and repair
Wired improperly
Check diagram
Pipe line blockage
Open valves
No delivery
Motor not running
Check power source. Check wiring diagram
Supply tank empty
Fill tank
Lines clogged
Clean and flush
Closed line valves
Open valves
Ball check valves held open with solids
Clean and inspect
Vapor lock, cavitation
Increase suction pressure
Prime lost
Reprime, and check for leak
Strainer clogged
Remove and clean. Replace screen if necessary
Low delivery
Motor speed too low
Check voltages, frequency, wiring, and Terminal
connections. Check nameplate vs. Specifications
Check valves worn or dirty
Clean, replace if damaged
Calibration system error
Evaluate and correct
Product viscosity too high
Lower viscosity by increasing product
temperature. Increase pump and/or piping size
Product cavitating
Increase suction pressure. Cool product as
necessary
Delivery
gradually drops
Check valve leakage
Clean, replace if damaged
Leak in suction line
Locate and correct
Strainer fouled
Clean or replace screen
Product change
Check viscosity
Supply tank vent plugged
Unplug vent
Delivery erratic
Leak in suction line
Locate and correct
Product cavitating
Increase suction pressure
Entrapped air or gas in product
Consult factory for suggested venting
Motor speed erratic
Check voltage and frequency
Fouled check valves
Clean, replace if necessary
Delivery higher
than rated
Suction pressure higher than
discharge pressure
Install backpressure valve or consult factory for
piping recommendations
Back pressure valve set too low
Increase setting
Back pressure valve leaks
Repair, clean, or replace
Pump loses
internal oil
Diaphragm ruptured
Replace
Leaky seal
Replace
Cover gasket leaks
Replace or retighten
Pump overfilled
Remove excess oil
Noisy gearing,
knocking
Discharge pressure too high
Reduce pressure
Water hammer
Install pulsation dampener
Stroke length at partial setting
Nondestructive knocking is characteristic of lost
motion pumps
No oil or level incorrect
Replace or refill oil