39
A.0500.751 – IM-TGBLOC/01.00 EN (10/2020)
Symptom
Cause
Remedy
Not enough capacity Viscosity too low
17 • Increase pump speed.
Attention!
Do not exceed
maximum speed and check NPSHr.
• If necessary, install a larger pump.
• If pump is heated by means of heating jackets or
electrical heating, reduce the heating input.
Axial clearance
18 • Check axial clearance and correct.
See section 3.20 Maintenance instructions.
Gases come free
19 • Increase pump speed.
Attention!
Do not exceed
maximum speed and check NPSHr.
• Install a larger pump
Pump too noisy
Pump speed too high
20 • Reduce pump speed.
If necessary, install a larger pump.
Cavitation
21 • Reduce difference between pump and suction
tank level.
• Increase suction pipe diameter.
• Reduce length and simplify suction pipe (use as
few elbows and other fittings as possible).
Also see section 3.17 Installation.
Back pressure too high
22 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.).
Vibration of pipings
23 • Make pipework better.
Ball bearings damaged or worn
24 • Replace ball bearings.
Pump consumes
too much power or
becomes hot
Pump speed too high
25 • Reduce pump speed.
If necessary, install a larger pump.
Viscosity too high
26 • Increase axial clearance.
See section 3.20 Maintenance instructions.
• Heat pump.
• Reduce pump speed.
• Increase discharge pipe diameter.
Rapid wear
Back pressure too high
27 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.)
Solid matter in liquid
28 • Filter liquid.
Pump runs dry
29 • Correct liquid supply.
• Provide level switch or dry running protection.
• Heat up liquid.
• Stop or reduce air sucking.
Corrosion
30 • Change pump materials or application
parameters.
Motor overloading
Back pressure too high
31 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.).
Viscosity too high
32 • Increase axial clearance.
See section 3.20 Maintenance instructions.
• Heat pump.
• Reduce pump speed.
• Increase discharge pipe diameter.
Pump leak
Mechanical seal leaks
33 • Replace mechanical seal.
Rapid wear of the
mechanical seal
Viscosity too high
34 • Heat the pump.
Bad de-aerating/ dry running
35 • Fill pump with liquid
• Check position of relief valve or top cover.
Temperature too high
36 • Reduce temperature.
• Install suitable mechanical seal.
Too long priming period/ dry running
37 • Reduce suction line.
• Provide dry running protection.
• Check maximum allowable dry running speed for
the mechanical seal.
Liquid is abrasive
38 • Filter or neutralise liquid.
Note!
If symptoms persist, the pump must be taken out of service immediately. Contact your local supplier.