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Problem
Discharge
volume is
small.
When Discharge
Valve is Closed
Pointers of
pressure gauge
and vacuum
gauge indicate
normal values.
Pointer of
pressure gauge
indicates low
value and that
of vacuum
gauge indicates
extraordinarily
low value.
When Discharge
Valve is Opened
Pointer of
vacuum gauge
indicates
extraordinarily
high value.
Pointers of
pressure gauge
and vacuum
gauge swing.
Pointer of
vacuum gauge
indicates a high
value while
that of pressure
gauge indicates
normal value.
Pointer of
pressure gauge
indicates high
value while
that of vacuum
gauge indicates
normal value.
Pointers of
pressure gauge
and vacuum
gauge indicate
low values.
Cause
K
Air is trapped in suction
pipe.
K
Inlet section of impeller
unit is clogged with
foreign matter.
K
Air enters through suction
pipe or gasket section.
K
Discharge side of pump is
clogged with foreign
matter.
K
There is an air trap or
resistance in suction pipe.
K
There is portion in dis-
charge pipe that causes
resistance, or actual head
and loss of head are too
high.
K
Rotation direction is re-
versed.
Inspection and
Countermeasures
K
Inspect setup condition of
suction pipe and modify it if
necessary.
K
Disassemble unit partially and
eliminate foreign matter.
K
Check connecting section of
suction pipe and tighten it if
necessary.
K
Eliminate foreign matter in the
pump.
K
Eliminate foreign matter or
scale inside pipe.
K
Check whether there is
protruding section in suction
pipe and take necessary
measures.
K
Check actual head and piping
loss of discharge pipe and take
necessary measures.
K
Exchange wires.
Symptom
