172-65608MA-03 (RGDS) 5 Oct 2021
16
Item
Cause
Diagnostic
Remedy
The pump
suction
pressure
gauge
indicates the
actual suction
pressure
The pump is
running empty
Water is not flowing into the pump
Open the pump inlet
valve and discharge
air
The pump is
running
backwards
The operating direction is incorrect Correct the wiring
The number of
rotations is too
low
Measure the number of rotations
with a tachometer
Correct the frequency
The lifting height
is lower
See the instruction manual for the
pump
Replace with a new
pump
Foreign matter is
clogging the
pump
Check if there is foreign matter in
the pump inlet
Clean the pump
The pressure
gauge on the
pump outlet is
broken
The pressure gauges on the pump
inlet and outlet show the same
pressure at shutdown
Replace with a new
pressure gauge
Steam or
desuperheating
water are not
supplied
The steam inlet
valve is still
closed
The inlet valve is closed
Open the inlet valve
The steam
pressure control
valve (CV) is still
closed; the
steam pressure
control valve
does not move
at all
Check the wiring to the control
valve; check the controller wire
connections; check the input signal
wiring for incorrect connections
Check the electrical
wiring diagram and
correct the wiring
Check that a signal of 4
– 20 mA is
being received by the CV at the
connection terminals
Adjust the controller or
positioner or replace
with a new controller
or positioner
Check the secondary pressure of
the steam pressure control valve; if
the electrical wiring and signal are
normal, then the steam pressure
control valve is malfunctioning
Disassemble, inspect
or replace the steam
pressure control valve
Check if air is being supplied to the
steam pressure control valve (CV)
positioner
Supply air to the
positioner
Does not reach
desired steam
pressure
The PID set
values are
incorrect
Check the PID set values
Correct the PID set
values
The pressure
sensor is
malfunctioning
Check the pressure value reading
from the sensor and compare with
the pressure gauge, if the electrical
wiring and signal are normal, then
the pressure sensor is
malfunctioning
Replace with a new
pressure sensor
Component(s)
inside the
pressure control
valve positioner
are broken
Check for abnormal sounds from
the positioner
Replace with a new
positioner
(Investigate whether
the valve aperture
changes frequently or
the ambient
temperature is too
high)
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