Dover PSG BLACKMER MLN4B, Инструкции по установке, эксплуатации и обслуживанию, Страница: 17 / 20

106-A00 Page 17/20
TROUBLESHOOTING
….continued
EXCESSIVE NOISE AND VIBRATION
Probable Cause Corrective Action
Cavitation or vaporization of the liquid resulting from
excessive vacuum on the pump due to starved suction. Check for:

Inlet piping too long or too small in diameter.

Strainer plugged or dirty.

Undersized or restrictive fittings, such as globe valves or partially
closed valves.

Excessive amount of elbows.

Suction lift too great.

Pump speed too high for the viscosity of the liquid being pumped.
Entrained air or vapors in the pump. Check pipe joints for leakage of air. Sometimes when recirculating
liquid in a tank, the returning liquid falling through the air carries air
down into the tank, which eventually gets back into the pump.
Rotor & Shaft installed backwards. The rotation arrow on the rotor must point towards the discharge port
when the arrow is located beneath the shaft.
(See Figure 6 on Page 9 or Figure 10 on Page 14.)
Liner Installed Backwards The word “INTAKE”, which is cast on the liner MUST be towards the
intake side of the pump
Pump speeds exceed the recommended maximum. Check the recommended RPM for your specific application.
Continual or long term bypassing of liquid through relief
valve. Check for restriction in the discharge line, or an improper relief valve
adjustment (See "Relief Valve" on Page 6).
OTHER POSSIBLE CAUSES OF NOISE AND VIBRATION:

Excessively worn vanes, liner, or discs.

Bearing Worn or Damaged.

Loose or improperly installed piping.

Misalignment of pump and driver.

Pump base not properly mounted.

Insufficient Oil in the Gear Reducer
LOW DELIVERY RATE
Probable Cause Corrective Action
Relief valve setting too low, causing the liquid to bypass. Set the relief valve 15 - 20 psi (1.0 - 1.4 bar) higher than the differential
pressure.
A dirty strainer. Clean the strainer regularly.
OTHER POSSIBLE CAUSES OF A LOW DELIVERY RATE:

Restriction in the suction line.

Resistance in the discharge line.

Air leaks in the suction line.

Damaged or worn pump parts.

Pump speed too low or too high.

Rotor & Shaft installed backwards.

Relief valve leaking.

Relief valve sticking open, or not properly seating.

Liner installed backwards
POOR OR NO PRIMING
Probable Cause

Air leaks in the suction line.

Restriction in the suction line.

Damaged or worn pump parts.

Too much lift for the vapor pressure of the fluid.

A dirty or clogged strainer.

Worn vanes.

Suction Valve Closed.

Incorrect pump rotation

Relief Valve partially open, valve not seating properly.