IM 01C25B01-01E
7-4
7. OPERATION
• Tighten the zero-adjustment cover mounting
screw to secure the cover.
7.4 Shutting Down the Transmitter
Shut down the transmitter as follows.
Steps 2) and 3) are specific to the differential pressure
transmitters.
1) Turn off the power.
2) Close the low pressure stop valve.
3) Open the equalizing valve.
4) Close the high pressure stop valve.
5) Close the high pressure and low pressure tap
valves.
NOTE
• Whenever shutting down the transmitter for a
long period, remove any process fluid that is in
the transmitter pressure-detector section.
• The equalizing valve must be left OPEN.
7.5 Venting or Draining Transmit-
ter Pressure-detector Section
Since this transmitter is designed to be self-draining
and self-venting with vertical impulse piping connec-
tions, 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
disturbs the pressure measurement, 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.
7.5.1 Draining Condensate
1) Gradually open the drain screw or drain plug and
drain the transmitter pressure-detector section. (See
figure 7.5.)
2) When all accumulated liquid is completely re-
moved, close the drain screw or drain plug.
3) Tighten the drain screw to a torque of 10 N·m, and
the drain plug to a torque of 34 to 39 N·m.
When you loosen the drain screw or drain
plug, the accumulated liquid will be expelled
in the direction of the arrow.
F0705.EPS
Drain screw
Drain plug
Figure 7.5
Draining the Transmitter
7.5.2 Venting Gas
1) Gradually open the vent screw to vent gas from the
transmitter pressure-detector section. (See figure
7.6.)
2) When the transmitter is completely vented, close
the vent screw.
3) Tighten the vent screw to a torque of 10 N·m.
When you loosen the vent screw, the gas
escpes in the direction of the arrow.
F0706.EPS
Vent screw
Vent screw
Figure 7.6
Venting the Transmitter
