Yokogawa EJX115A - Manual (Page 36)

<7. Operation>
7-6
IM 01C25K01-01E
7.6 Venting or Draining
Transmitter Pressure-
detector Section
Since this transmitter is designed to be self-
draining and self-venting with vertical impulse
piping connections, neither draining nor venting
will be required if the impulse piping is configured
appropriately for self-draining or self-venting
operation.
If condensate (or gas) collects in the transmitter
pressure-detector section, the measured pressure
may be in error. If it is not possible to configure the
piping for self-draining (or self-venting) operation,
you will need to loosen the drain (vent) screw on the
transmitter to completely drain (vent) any stagnated
liquid (gas).
However, since draining condensate or bleeding off
gas gives the pressure measurement disturbance,
this should not be done when the loop is in
operation.
WARNING
Since the accumulated liquid (or gas) may be
toxic or otherwise harmful, take appropriate care
to avoid contact with the body, or inhalation of
vapors.
7.6.1 Draining Condensate
1) Gradually open the drain screw or drain plug
and drain the transmitter pressure-detector
section. (See Figure 7.6.1.)
2) When all accumulated liquid is completely
removed, close the drain screw or drain plug.
3) Tighten the drain screw to a torque of 10 N·m
{1kgf·m}, and the drain plug to a torque of 34 to
39 N·m {3.5 to 4 kgf·m}.
F0708.ai
Drain screw
Drain plug
When you loosen the drain screw or drain
plug, the accumulated loquid will be
expelled in the direction on th earrow.
Figure 7.6.1 Draining the Transmitter
7.6.2 Venting Gas
1) Gradually open the vent screw to vent gas from
the transmitter pressure-detector section. (See
Figure 7.6.2.)
2) When the transmitter is completely vented,
close the vent screw.
3) Tighten the vent screw to a torque of 10 N·m
{1kgf·m}.
F0709.ai
Vent screw
Vent screw
When you loosen the vent screw, the gas
escapes in the direction of the arrow.
Figure 7.6.2 Venting the Transmitter
7.7 Setting the Range Using the
Range-setting Switch
WARNING
The range setting switch must not be used in the
hazardous area.
When it is necessary to use the switch, operate it
in a non-hazardous location.
When pressure is applied to the transmitter, the low-
and high-limit values for the measurement range
(LRV and URV) can be changed (re-ranged) using
the range-setting switch (push-button) located on
the optional integral indicator plate and the external
zero adjustment screw. This procedure does
not require use of the communicator. However,
changes in the scale range and engineering unit
display settings for the integral indicator require use
of the communicator.
Follow the procedure below to change the LRV and
URV settings.