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■
EPDT-318a
■
10
.
Maintenance and inspection
10.1 Troubleshooting (Please see the structure described 4)
Problem
Cause
Solution
Not working
1
.
Operating pneumatic
pressure or external signal
are not supplied.
1
.
Please confirm the presence or
absence of the operating air
(more than 0.35MPa) by the
pressure gauge, etc. And
confirm the external signal
tester by using tester.
2
.
Air piping is clogged or
leaked.
2
.
In case of clogged, please clean
it. When leaking, please replace
the piping.
3
.
Diaphragm bolt is loosen.
3
.
Retighten it.
4
.
Leakage is happened
between bottom diaphragm
case and diaphragm rod.
4
.
Replace the product.
5
.
Failure is occurred on
accessories of positioner or
regulator.
5
.
Inspect or replace the positioner
or regulator.
6
.
Failure is occurred on body
part or actuator
6
.
Inspect or replace the product.
7
.
Sensitivity of the positioner is
inadequate.
7
.
Replace the positioner.
Working is
unstable
1
.
Abnormal signal from the
controller
1
.
Adjust controller again and
confirm the signal system.
2
.
Operating pneumatic
pressure is not constant.
2
.
Check the air piping and
exchange it to the bigger piping
diameter.
Leakage from
valve
⑤
1
.
The valve does not move to
the full closed position ( Not
moving downward )
1
.
Adjust the zero point again by
using the controller.
2
.
There are any scratches on
the valve seat
③
1 or valve
⑤
2
.
Replace the product.
Leakage from
grand packing
⑥
or gasket part
⑧
1
.
The nut on grand part
⑳
or
body part
⑪
is loosen.
1
.
Retighten the nut. After
retightening, there is still leak,
exchange the packing.
2
.
The harden pf the grand
packing
⑥
or gasket
⑧
2
.
Replace them.