Johnson Pump TG GS2-25 Instruction Manual page 41

Symptom
Not enough capacity Viscosity too low
Pump too noisy
Pump consumes
too much power or
becomes hot
Rapid wear
Motor overloading
Pump leak
A.0500.501 – IM-TGGS/05.01 EN (03/2013)
Cause
Axial clearance
Gases come free
Pump speed too high
Cavitation
Back pressure too high
Coupling misalignment
Vibration of base plate or pipings
Ball bearings damaged or worn
Pump speed too high
Coupling misalignment
Viscosity too high
Back pressure too high
Solid matter in liquid
Pump runs dry
Corrosion
Back pressure too high
Viscosity too high
Mechanical seal leaks
Remedy
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.
18 • Check axial clearance and correct.
See section 3.21 Maintenance instructions.
19 • Increase pump speed. Attention! Do not exceed
maximum speed and check NPSHr.
• Install a larger pump
20 • Reduce pump speed.
If necessary, install a larger pump.
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 3.18 Installation.
22 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.).
23 • Check and correct alignment.
Also see section 3.18 Installation.
24 • Make baseplate heavier and/or fix base plate/
pipework better.
25 • Replace ball bearings.
26 • Reduce pump speed.
If necessary, install a larger pump.
27 • Check and correct alignment.
Also see section 3.18 Installation.
28 • Increase axial clearance.
See section 3.21 Maintenance instructions.
• Heat pump.
• Reduce pump speed.
• Increase discharge pipe diameter.
29 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.)
30 • Filter liquid.
31 • Correct liquid supply.
• Provide level switch or dry running protection.
• Heat up liquid.
• Stop or reduce air sucking.
32 • Change pump materials or application
parameters.
33 • Increase pipe diameter.
• Reduce working pressure.
• Check accessories (filter, heat exchanger, etc.).
34 • Increase axial clearance.
See section 3.21 Maintenance instructions.
• Heat pump.
• Reduce pump speed.
• Increase discharge pipe diameter.
35 • Replace mechanical seal.
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