A-2
Appendix A
Model 752 and 752A Differential Pressure Transmitters
Typical Piping/Startup Examples
Diagrams for typical and special flow applications are presented on the fol
-
lowing pages. Use the diagram best suited for the application as a guide for
piping configuration.
Gas Flow, DPU Above Run
The following steps are recommended for applications in which hydrates are
NOT present.
1.
Open the bypass valve(s) and close the vent valve.
2.
Open both shutoff valves and one block valve to pressurize DPU, then
close the block valve.
3. Close one bypass valve and check the system for leaks. If output travels
upscale, check for low-pressure piping leaks. If output travels downscale,
check for high-pressure piping leaks.
4. Repair piping if necessary and repeat steps 1 through 3 until output
remains stable at zero.
5. Close both shutoff valves and open the bypass valve(s).
6.
Open both block valves and slowly open both shutoff valves.
7. Close the bypass valves, and if two bypass valves are used, open the vent
valve.
BLOCK VALVES
PRIMARY DEVICE
STATIC PRESSURE
CONNECTION
(USE ONLY ONE)
BYPASS
VALVES
VENT VALVE
SHUT-OFF
VALVES
DPU
Figure A.1—Gas Flow, DPU Above Run
