TROUBLESHOOTING
NA Series Operating & Instruction Manual
Page 34
PROBLEM
PROBABLE CAUSE
SOLUTION
NO FLO
W
Pump has lost its prime
Reduce liquid temperature.
Check inlet line for air leaks.
Check for loss of liquid supply.
Re-prime pump. Refer to OPERATION
section.
Blocked inlet line
Check for blockage in the inlet pipework.
Check if any inlet strainers / filters are
blocked.
Check for closed valves in the inlet
pipework.
Motor has stopped
Check power supply.
Check motor condition.
EXCESSIVE
FLOW
Actual total discharge head is
below rated head of pump
Reduce speed of rotation if possible.
Fit smaller diameter impeller.
Partly close discharge valve to restrict
flow.
Fit orifice plate in discharge line to
restrict flow.
M
OT
OR
OV
E
R
HEA
T
S
AN
D
/ OR
C
UT
S
O
UT
Actual total discharge head is
below rated head of pump
Reduce speed of rotation if possible.
Fit smaller diameter impeller.
Partly close discharge valve to restrict
flow.
Fit orifice plate in discharge line to
restrict flow.
Excessive liquid density
Reduce flow rate by partly closing
discharge valve.
Reduce flow rate by introducing an
orifice plate into discharge line.
Pump has or is about to seize
Check pump for free rotation.
Check pump internally for obstructions.
Motor and pump misaligned
Refer to INSTALLATION section.
Undersized motor
Fit a larger motor: check first with you
pump supplier.
Incorrectly set motor overload cut
out
Check motor overload setting
Electronic dry running protector
has tripped
Check for loss of flow.
Check for loss of liquid supply.
