WIKA BWX - Manual (Page 5)

INSTRUCTION MANUAL
NI-222E
Rev. 1 12/02
CAUTION: fittings used for the electrical connection of
the pressure switch Series BAX (explosionproof) shall be
certified to Standards EN 50014 and 50018, and shall
guarantee instrument degree of protection (IP65).
Check that there is no power in the lines.
Remove the cover and carry out the cabling and connec-
tions to the terminal block (see Fig. 2).
Flexible cables with a maximum section of 1.2 mm
2
(16AWG) are recommended using the pre-insulated fork
thimbles. Do not touch the adjustment screws and do
not bend the elastic microswitch supports in order to
prevent the instrument calibration being altered.
Ensure that no deposits or wire ends remain inside the
case.
As soon as connection steps are completed, mount the
cover on and make sure it is tight and blocked See Fig. 3
and 4.
6.4 SPECIAL NOTE FOR INSTALLATION OF
CATEGORY 1 / 2 G PRESSURE SWITCHES
Explosionproof pressure switches (Series BAX) can be
installed on processes requiring apparatus of group II
category 1 in an ambient requiring apparatus of group II
category 2 (see Fig. 6).
Fig. 6 - Installation of Group II Cat. 1 / 2 G instruments
7 - INSTRUMENT PLUMBING
Weatherproof pressure switches (Series BWX)
The plumbing, aimed as a guarantee against possible
tampering of the calibration and electrical connections,
can be carried out using a flexible steel wire (c) inserted
into the holes in the screw (a) and the bracket (e) pro-
vided for this purpose (see Fig. 3).
Explosionproof pressure switches (Series BAX)
Plumbing is not necessary as the cover is blocked with a
headless screw, the closure plugs of the adjustment
screw access holes are blocked by means of the internal
blocking device and the instrument does not have to be
opened when installed.
8 - PUTTING INTO OPERATION
As the signal transmitted by the instrument is used in a
complex system, it is necessary that the means of put-
ting it into operation are established by those in charge
of the plant.
The instrument comes into operation as soon as 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.
In case of explosionproof instruments (Series BAX),
initial inspections are to be carried out according to cus-
tomer procedures and at least in accordance with Stan-
dard EN-60079-17.
9 - FUNCTIONAL VERIFICATION
This will be carried out according to the Client’s control
procedures. Series BWX instruments can be verified on
the plant if installed as illustrated in Fig. 7 and 8.
The instruments Series BAX may be checked on site
only if apparatus suitable for explosives atmosphere are
used and provided that the electric line is not
energized.
If this is not the case it is necessary to stop operation,
dismount by means of the three-piece joints and carry
out the verification in a test room.
CAUTION: do not open the cover of explosionproof
pressure switches (Series BAX) when energized, in
explosive atmospheres.
Verification consists in checking the calibration value
and possibly regulating the adjustment screw (see §4 ).
In case of explosionproof instruments (Series BAX),
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.