Putting Into Operation; Visual Inspection; Functional Verification; Stopping And Dismounting - WIKA mw series Instruction Manual

10

PUTTING INTO OPERATION

The instrument comes into operation as soon as is energized and
the root valve is opened. Any possible drainage of the connection
tubing can be carried out by removing the safety plug and opening
the service valve with the necessary caution.
Do not dispose of the process fluid into the environment, if this can
cause pollution or damage to people
11

VISUAL INSPECTION

Periodically check the external condition of the enclosure. There
should be no trace of leakage of process fluid outside the instru-
ment.
In case of flameproof or intrinsic safety instruments, inspections of
the electrical installation are to be carried out also according to
customer procedures and at least in accordance with Standard
EN-60079-17.
The flameproof and the intrinsic safety instruments installed in ex-
plosive atmospheres for the combustible dust presence, must be
periodically cleaned up externally in order to avoid dust accumu-
lating.
11.1
INSTRUMENT WITH SENSOR TYPE H AND G
The switches equipped with sensing element type H or G are in-
strument with a piston sensing element. The process connection
of such instrument have a hole to check the wear of the O-ring
seal. During the visual inspection check the absence of fluid into
the position of Fig.15. On the contrary the instrument have to be
replaced.
Fig. 15 – Hole to check the wear of the O-ring seal
11.2
INSTRUMENTS WITH PROCESS CONNECTION COATED
WITH PTFE
These instruments are usually installed on process with high cor-
rosion resistance requirements. To verify the condition of PTFE the
process connection is equipped with an inspection hole. During the
visual inspection check the absence of fluid into the position of
Fig.16. On the contrary the instrument have to be replaced.
Fig. 16 – Hole to check the wear of the PTFE coating
INSTRUCTION MANUAL
12
This will be carried out according to the Customer's control proce-
dures. Model M instruments can be verified on the plant if installed
as illustrated in Fig. 21 and 22.
To avoid any risk it is recommended check the set point on site
without open the cover and without dismount the cable gland and
without unplugging the power cable.
The flameproof or intrinsic safety instruments may be checked on
site only if the apparatus used are suitable for explosive
atmosphere.
If this is not the case it is necessary remove the instrument from
the plant, and carry out the verification in a test room.
If the verification of the set point is performed unplugging the power
cable from the terminal block it is recommended de-energize the
instrument to avoid any electrical hazard.
WARNING: Instrument model MA, flameproof.
Before open the cover or the cable gland check the absence of
explosive atmosphere and check that the instrument is not
energized.
Verification consists in check the calibration value and possibly
regulating the adjustment bush (see §6).
12.1
TYPE G
This instrument, because of their particular operating principle, if
used as an alarm of max pressure, have to be functional inspected
every year as minimum.
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Before proceeding with these operations ensure that the plant or
machines have been put into the conditions foreseen to allow
these operations.
With reference to Figures 21 e 22
Remove the power supply (signal) from the electrical line. Close
the root valve (6) and open the drain. Remove the plug (2), open
the valve (3) and wait until the process fluid has drained from the
tubing through the drain.
Do not dispose of the process fluid into the environment, if this can
cause pollution or damage to people.
Unscrew the three-piece joint (8).
WARNING: Instrument model MA, flameproof.
Before open the cover or the cable gland check the absence of
explosive atmosphere and check that the instrument is not ener-
gized.
Unscrew the three-piece joint (10) (electrical cable tubing).
Remove the instrument cover and disconnect the electrical cables
from the terminal block and earth screws.
Remove the screws fixing the case to the panel (or pipe) and re-
move the instrument, taking care to slide the electrical conductors
out from the case.
Mount instrument cover. Insulate and protect cables around, if any.
Temporarily plug pipes not connected to the instrument.
In case of flameproof instruments or intrinsic safety it is recom-
mended to follow - at least – the standard EN-60079-17 for the
withdrawal from service of electrical apparatus.
14
The instruments are mainly made of stainless steel and aluminium
and therefore, once the electrical parts have been dismounted and
the parts coming into contact with fluids which could be harmful to
people or the environment have been properly dealt with, they can
be scrapped.

FUNCTIONAL VERIFICATION

INSTRUMENT WITH DIAPHRAGM SEAL OR SENSOR

STOPPING AND DISMOUNTING

DISPOSAL

NI-221WE
Rev. 5 12/16
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