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11. Troubleshooting
Difficulty Probable Cause Remedy
Faulty power source. Check power source.
Blown fuse, circuit breaker. Replace - eliminate overload.
Broken wire. Locate and repair.
Wired improperly. Check diagram.
Pump does not start
Process piping blockage. Open valves, clear other obstructions.
Motor not running. Check power source. Check wiring
diagram (see above).
Supply tank empty. Fill tank.
Lines clogged. Clean and flush.
Closed line valves. Open valves.
Ball check valves held open with solids. Clean – inspect, flush with clear fluid.
Vapor lock, cavitation. Increase suction pressure.
Prime lost. Re-prime, check for leak.
Strainer clogged. Remove and clean. Replace screen if
necessary.
No delivery
Stroke adjustment set at zero. Increase stroke length setting.
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 or dilution. Increase pump
and/or piping size
Low delivery
Product cavitating Increase suction pressure.
Check valve leakage. Clean, replace if damaged.
Leak in suction line. Locate and correct.
Strainer fouled. Clean or replace screen.
Product change. Check viscosity and other variables.
Delivery gradually
drops.
Supply tank vent plugged. Unplug vent.
Leak in suction line. Locate and correct.
Product cavitating. Increase suction pressure.
Entrained air or gas in product. Consult factory for suggested venting.
Motor speed erratic. Check voltage and frequency.
Delivery erratic.
Fouled check valves. Clean, replace if necessary.
Inadequate backpressure Increase discharge pressure to obtain a
minimum pressure difference of 5 pis
from suction to discharge
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.
Delivery higher than
rated.