A-6
Appendix A
Model 752 and 752A Differential Pressure Transmitters
Liquid Flow, DPU Above Run
The following steps are recommended for applications in which sediments
may be present. Inspect piping periodically. Not recommended for hot or
gassy liquids.
1. Close both shutoff valves and open both block valves.
2.
Open the bypass valve. Crack the vent valves or loosen the plugs from
the top ports of the DPU body housings.
3. Crack and close the shutoff valves alternately until liquid is free of
bubbles and spills out of both upper DPU body ports.
4. Close the vent valves or tighten the plugs. Close the block valves and
open the shutoff valves.
5.
The pointer should rest at zero (or output will be 4 mA or 10 mA as ap
-
plicable). If it does not and no leaks are detected, the housing and/or pip-
ing are not completely filled with liquid. Repeat steps 1 through 4 until
output remains stable at the lowest value.
6. Slowly open both block valves and close the bypass valve.
BLOCK VALVES
PRIMARY
DEVICE
BYPASS
VALVE
SHUT-OFF
VALVES
DPU
Figure A.5— Liquid Flow, DPU Above Run
