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. |