6-2
Chapter 6. MAINTENANCE AND TROUBLESHOOTING
•
If the causes of the alarm are removed, the alarm display turns off
automatically. However, when "2, -2: Forced fully closed" or "3, -3: Forced
fully open" is selected for
c-
16
in the function setup, the alarm display and
operating mode at alarm occurrence are retained even if the causes of the
alarm are removed.
z
Alarm reset operation
When the ENT key is kept pressed continuously while the instantaneous flow rate is
being displayed, the alarm is reset after 3 seconds have elapsed.
Troubleshooting guide
Observation Causes Remedy
Flow rate display does not become
zero even with an actual zero flow
rate.
•
The device is installed on the vertical
(or inclined) piping.
•
Install in horizontal piping or use the
forced PV zero function (function setup
C-29
).
(Display is not
Off
even if the valve
is fully closed.)
•
Condensation on sensor
•
Zero point of sensor has deviated
•
Foreign object on sensor
•
Insert a mist trap upstream.
•
Adjust the flow rate zero
•
Ask for repair.
Flow rate does not stabilize.
•
Operating differential pressure range is
exceeded.
•
Lower the primary pressure.
•
Inlet pressure fluctuates greatly.
•
Regulator interference
•
Insert a regulator upstream.
•
Change the pressure setting on the
pressure regulator or increase the
capacity of the pipe between the MQV
and the regulator.
•
Apply the instantaneous PV filter
(function setup
C-23
).
•
Large pressure loss in piping (inlet
pressure fluctuates greatly according
to flow rate.)
•
Use larger diameter pipe.
•
In the case of a device causing a
large pressure loss, either remove the
device or install larger capacity piping
between the MQV and the device.
•
Check valve vibration.
•
Change the check valve to one having
a low cracking pressure.
•
Operating differential pressure setting
(function setup
C-36
) does not match
the actual operating differential
pressure.
•
Adjust the operating differential
pressure setting to the actual operating
differential pressure or set "2" for the
operating differential pressure setup.
Poor accuracy
•
Temperature reference does not match
the reference flow meter.
•
Regulator is vibrating slightly.
•
Foreign object stuck on sensor
•
Match the temperature reference.
(Change in
C-
19
in the function setup.)
•
Change the regulator pressure setting.
•
Ask for repair.
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