Flowgrid Regulator | 13
Standby Monitor
Working Monitor
1. Purge station and open outlet valve or vent to allow flow
through the station.
2. Set pilot (#3) to a high setting above desired setpoint.
3. Set pilot (#1) to a high setting above desired setpoint.
4. Set the Monitor pilot (#2) at a zero setting.
5. Set restrictor on Pilot (#1) at an intermediate opening (a
“4” setting on the Mooney Type 24 Restrictor).
6. Slowly open the inlet block valve to station. The 1st Stage
Regulator should remain closed as a result of the Monitor
Pilot (#2) being set to zero.
7. Increase the setting of the Monitor Pilot (#2) to the
desired pressure setting. If the valve is unstable, increase
the restrictor opening until it becomes stable
8. Lower the setpoint of the 2nd stage regulator (Pilot #3) to
the desired outlet pressure setting. Tune the restrictor on
Pilot (#3) at this time. The 1st stage regulator should open
or begin to control the interstage pressure at the setpoint
of Pilot (#1).
9. Adjust the setpoint of Pilot (#1) to achieve the desired
Interstage pressure. Tune the restrictor on Pilot (#1) at this
time.
10. Raise the setpoint of Pilot (#3) to verify the setpoint of the
Monitor Pilot (#2). Adjust if necessary. Check for system
stability and adjust the restrictor on Pilot (#1) if required.
11. Return setpoint of Pilot (#3) to maintain the desired outlet
pressure..
Figure 10. Working Monitor Schematic
NOTE: In a working Monitor system with less than 25 psig differential across the second stage
regulator the pilot supply may be connected to the piping upstream of the first stage regulator.
This will improve the shutoff of the second stage regulator.
Maintenance
Regulator parts are subject to normal wear and must be
inspected and replaced as necessary. The frequency of
inspection and replacement of parts depends on severity
of service conditions or the requirements of local, state,
and federal regulations. Be certain that the name plates are
updated to accurately indicate any field changes in equipment,
materials, service conditions, or pressure settings.
Before disassembly make sure the regulator has been isolated
from the process by closing block valves on the inlet and outlet
sides of the regulator. Safely release pressure and process
fluid from body and pilot system. Failure to complete these
steps can result in personal injury and property damage.