Kofloc 8700 MC, Instruction Manual

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MJ400306A1
31
4. The set indication
cannot be obtained.
a. The pressure on the inlet side of the
mass flow controller is too high or the
controller is faulty. Or, a pressure
difference between the inlet side and
outlet side is not adequate.
1. Adjust the pressure to the adequate level as shown
in the brochure or set an adequate differential
pressure.
b. The pressure loss of piping is large. Or
the pressure loss has increased as the
filter, check valve, etc. has become nearly
clogged.
2. Set a pressure gauge immediately before and after
the mass flow controller and check to see if the
pressure difference is adequate. Make adjustment to
get an adequate differential pressure.
c. The orifice in the control valve is almost
clogged.
3. If the problem is solved by increasing the pressure,
it is most likely that the orifice is clogged. To replace
the orifice, please send it to KOFLOC.
5. The flow rate is clearly
less that the indicated flow
rate.
a. The piping line is leaking. 1. Using the evacuation method, leak detect fluid, etc.,
investigate causes of leak such as failure to tighten
piping line nuts, insufficient tightening of such nuts or
others and retighten the nuts of leaking places or take
other corrective actions to stop leak.
b. The mass flow main unit is leaking. 1. Same as above. When checking leak using leak
detect fluid, apply such fluid only to the joints before
and after the unit, but do not apply it to the inside of
the main unit cover. After checking, wipe off leak
detect fluid completely so that it will not remain at all.
c. The bypass is clogged. 1. To replace the bypass part, please send it to
KOFLOC.
6. The flow rate is clearly
larger than the indicated
flow rate.
a. The sensor tube is nearly clogged.
1. To replace the sensor tube, please send it to
KOFLOC.
7. Even if the command is
set to zero, gas keeps
flowing.
a. The equipment is not in the analog
setting mode. Or, the external input set
voltage is not zero. Or, the printed board is
faulty. Or, the wiring of the command
soldered part is broken.
1. Change the equipment to the analog setting mode
and check the operation. If the operation will not
become normal, check the external input set voltage.
2. Input the valve forced close signal GND to Pin No. 8
and see if gas stops. If gas does not stop, the valve needs
to be readjusted. Please send it to KOFLOC.
If gas stops, a possible cause is a faulty electronic
circuit. Please send it to KOFLOC.
b. Internal leak due to adhesion of dust,
etc. to the sealing area of the control valve.
1. To overhaul and clean the control valve, please send
it to KOFLOC.
c. The zero point voltage has moved to the
negative side.
1. The zero point voltage is abnormal. See Symptom 2.
The output will not become zero.