
29
Flow noise.
Operation contrary to design in overload
or part-load range.
Adjust working point to design.
Flow losses in suction line too high.
Increase nominal sizes;
shorten connection lines;
prevent outgassing.
Cavitation.
Check condition for NPSH rating;
contact
Fristam
.
Vibrations.
Suction and discharge lines stressing pump
impermissibly.
Support pipes so that
pump is not stressed;
possibly install vibration dampers;
keep water hammers away from pump.
Excessive heating of shaft bearing.
Bearing damage.
Replace bearing.
Motor power consumption too high.
Flow rate too high.
Throttle discharge line or
reduce speed with frequency converter.
Impeller diameter too large.
Trim impeller diameter;
contact
Fristam
.
Viscosity and/or density of
pumped product too high.
Contact
Fristam
.
Massive damage to shaft bearing;
shaft deformed.
Disassemble, inspect, and
have repaired by
Fristam
.
Leakage at shaft seal.
Impeller nut loose.
Remove impeller,
inspect shaft shoulder,
check shaft seal,
tighten impeller nut to required torque, and
possibly replace part.
Mechanical seal or rotary shaft seal mechanical
damage or wear.
Replace shaft seal and elastomers;
possibly convert to different materials;
contact
Fristam
.
Shaft seal running dry;
suction head too high;
pumping media temperature too high.
Increase pump inlet pressure;
decrease suction head;
use double shaft seal;
contact
Fristam
.
Sealing water head too high.
Adjust using throttle valve.
Sealing water head too low.
Replace rotary shaft seal.
Sealing water tubes clogged
(resulting in damage to rotary shaft seal);
sealing water not clean.
Clean sealing water tubes;
adjust sealing water inlet and outlet;
use drinking water-quality water with tempera-
ture of max. 70°C.
Temperature of pumping medium too high.
Contact
Fristam
;
convert to double shaft seal.
Viscosity and/or density of pumped product too
high.
Contact
Fristam
.
1
The "geodesic suction head" is the vertical distance between the suction-side liquid level and the center of the impeller.
Problem
Possible Cause
Remedy
Table 13 Troubleshooting table