TROUBLESHOOTING
NA Series Operating & Instruction Manual
Page 35
PROBLEM
PROBABLE CAUSE
SOLUTION
PUMP R
UN
S
NOI
S
ILY AND /
OR
VI
BR
A
TES
Low inlet pressure, with
cavitation, loss of efficiency and
loss of liquid film in the pump
bearings.
STOP THE PUMP
IMMEDIATELY!
(Mechanical damage may be
occurring)
Decrease suction lift (negative head).
Increase static suction (positive head)
Check for inlet obstructions or
restrictions.
Reduce liquid temperature.
Increase inlet pipework bore.
Decrease length of inlet pipework.
Open inlet valve fully.
Check for excessive liquid viscosity:
increase liquid temperature if necessary.
Reduce liquid temperature
Motor and pump misaligned
Refer to INSTALLATION section.
Coupling worn
Replace coupling.
Check alignment of motor and pump.
Worn external pump bearings
Check bearings and replace if necessary
Worn motor bearings
Check bearings and replace if necessary
Pump feet, motor feet or
baseplate not firmly secured
Check for ‘soft-foot’. Refer to PUMP
FOUNDATION section.
Misaligned or badly secured
pipework
Check pipework alignment and support.
Refer to LOCATION AND PIPING section.
Pump starting while rotating in
reverse
Stop pump immediately and allow
discharge line to drain completely before
re-starting.
