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INFORMATION - TROULBESHOOTING


Centrifugal pump troubleshootingDiaphragm pump troubleshootingPiston pump troubleshootingPlunger pump troubleshootingRoller pump troubleshooting
CENTRIFUGAL PUMPS
Symptom Probable Cause(s) Corrective Action
Low Discharge Pump not primed. Remove topmost vent plug from face of pump and run pump to expel trapped air (See Installation Instructions).
Air leaks in suction line. Check and reseal inlet fittings.
Blocked or clogged line strainer. Inspect strainer and clear any debris from screen.
Impeller plugged. Inspect and clear obstruction.
Undersize suction line or collapsed hose. Suction line should be the same diameter as inlet port of pump or larger.
Improperly sized hydraulic motor. Refer to Pump Selection Guide to determine proper size hydraulic motor for your hydraulic system.
Bypass Adjustment Screw not set properly. Adjust bypass screw on side of hydraulic motor in, until the desired output is attained.
Eye of impeller rubbing on volute. Remove volute (front cover) and inspect the impeller. If wear detected, sand the impeller eye O.D. with emery cloth.
Hydraulic system overheating Improper hydraulic motor size. Refer to Pump Selection Guide to determine proper size for your hydraulic system.
Bypass Adjustment Screw set to bypass too much oil. Close adjustment screw on side of hydraulic motor to lessen the amount of oil being bypassed.
Improper metering orifice installed in pressure port. Install proper size orifice. Refer to Installation section for proper sizing.
Insufficient hydraulic hose size. Check hydraulic hose size. Hose should be at least 1/2". For large open-center systems 3/4".

DIAPHRAGM PUMPS
Symptom Probable Cause(s) Corrective Action
The pump does not draw water. One or more valves are seating improperly. Remove valve and check for debris.
Suction line is plugged or collapsed. Clogged strainer. Examine suction line. Clean strainer.
The liquid flow is irregular. The charge in the pulsation dampener is incorrect. Check pressure in pulsation dampener (20% working pressure).
One or more valves are seating improperly. Remove valve and check for debris. Examine the valve seatings and clean them.
Output drops and the pump is noisy. Oil level is too low. Add oil to correct level (halfway up the sight tube).
Oil comes out of the discharge port or oil is a milky color. One or more diaphragms split. Remove manifold and heads. Drain oil and clean crankcase of water. Replace diaphragms, heads and manifold. Refill with Hypro Oil (Part Number 2160-0038).

PISTON PUMPS
Symptom Probable Cause(s) Corrective Action
No Flow or Low Flow Pump not primed Refer to Priming in the Operation Section.
Air leaks in suction line Check and reseal inlet fittings.
Blocked or clogged line strainer Inspect strainer and clear any debris from screen.
Undersize suction line or collapsed hose Suction line should be the same diameter as inlet port of pump or larger.
Nozzle clogged Clear nozzle or replace.
Unloader or relief valve not functioning properly Repair or replace relief valve.
Low pressure Debris in valves Remove debris. See Repair section.
Valves worn Replace valves. See Repair section.
Unloader or relief valve not functioning properly. Repair or replace relief valve.
Pump is not primed. See priming in Operation section.
Pump Leaking Seals worn Replace seals.
Body cracked Replace body.

PLUNGER PUMPS
Symptom Probable Cause(s) Corrective Action
Pump runs but produces no flow. Pump is not primed. Flood suction then restart pump.
Pump fails to prime. Air is trapped inside pump. Disconnect discharge hose from pump. Flood suction hose, restart pump, and run pump until all air has been evacuated.
Pump loses prime. Chattering noise, pressure fluctuates. Air leak in suction hose or inlet fittings. Remove suction hose and test for leaks pressurizing hose with water. Make sure thread sealant has been used on all fittings
Suction line is blocked, collapsed or too small. Remove suction line and inspect it for a loose liner or debris lodged in hose. Avoid all unnecessary bends. Do not kink hose.
Clogged suction strainer. Clean strainer.
Low pressure at nozzle. Unloader valve is bypassing. Make sure unloader is adjusted properly and bypass seat is not leaking.
Incorrect or worn nozzle. Make sure nozzle is matched to the flow and pressure of the pump. If the nozzle is worn, replace.
Restricted intake. Refer to above priming information.
Pressure loss in general. Screen clogged. Check the screen for debris and clean or replace.
Inlet size too small. Make sure it is big enough.
Worn or clogged valves are stuck due to rust. Inspect valves for rust, wear pitting and debris and replace if necessary.
Unloader bypassing. Plumbed wrong. See if the flow is diverting out of the bypass line.
System leaks. Check for leaks

ROLLER PUMPS
Symptom Probable Cause(s) Corrective Action
Pump does not prime. Leak in suction line. Check hose and fittings for leaks and correct.
Obstruction in suction line. Inspect hose for obstruction such as debris or loose inner liner.
Suction hose sucked to bottom or side of tank. Cut a notch or "V" in end of suction hose.
Rollers stuck in pump. Disassemble pump and inspect rollers
Pump seals leaking air. Replace seals.
Pump turning in wrong direction. Correct rotation of pump (See Reversing Pump).
Loss of pressure. Clogged suction strainer. Check strainer and clean it regularly.
Kinked or blocked suction hose. Inspect suction hose and repair as necessary.
Air leak in inlet side plumbing. Chose hose and connections for leaks. Use pipe joint sealant and re-tighten connections.
Relief valve setting too low or weakened spring. Check relief valve and correct setting or replace weakened spring.
Faulty gauge. Replace gauge
Pump seals leak air. Replace seals.
Nozzle orifices worn. Replace nozzles.
Pump worn. Repair pump (See Repair Instructions).
Pump will not turn. Corrosion (rust), scale or residue Loosen endplate bolts. Squirt oil into ports to help free rotor. Re-tighten bolts.
Solid object lodged in pump. Disassemble pump and remove objects.

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