Fisher EZL Instruction Manual page 8

Type EZL
Regardless of which regulator is used as the monitor,
it should be equipped with a pilot supply regulator
set to limit the pilot supply pressure to 10 to 15 psig /
0.69 to 1.0 bar above control pressure. Since the
pilot on the monitoring regulator is wide-open during
normal operation, the pilot supply regulator is used
to prevent differential pressure relief valve chatter on
the monitoring regulator pilot.
Working Monitor Regulator (Figure 5)
1. Follow the procedure in the All Installations
section, and then continue with step 2 of
this section.
2. Attach 3/8 inch / 9.5 mm tubing (for Types 161M
and 161EBM) downstream control line to the control
line (sense) connection on the pilot. Connect
the other end of the control line to the pipeline
downstream of the downstream working regulator.
Do not attach the control line near any elbow,
swage, block valve, or any other location that might
cause turbulence.
3. Apply pilot sense pressure by connecting the
outlet of the monitor pilot to the inlet of the working
monitor pilot.
Startup and Adjustment
Pre-startup Considerations
Each regulator is factory-set for the outlet pressure
specified on the order. If no setting was specified,
outlet pressure was factory-set at the mid-range of
the pilot control spring. Before beginning the startup
procedure in this section, make sure the following
conditions are in effect:
• Block valves isolate the regulator
• Vent valves are closed
• A bypass, if any, is in operation
In all cases, check the control spring setting to make
sure it is correct for the application.
CAUTION
Be sure to slowly introduce pressure
into the system to prevent downstream
overpressure due to potential rapid
pressure increase. Pressure gauges
should always be used to monitor
downstream pressure during startup.
Procedures used in putting this
8
regulator into operation must be planned
accordingly if the downstream system is
pressurized by another regulator or by a
manual bypass.
Startup
1. Make sure all block valves, vent valves, and
control line valve(s) are closed.
2. Back out the pilot adjusting screw(s).
3. Slowly open the valves in the following order:
a. Pilot supply and control line valve(s), if used.
b. Inlet block valves.
4. Crack open the outlet block valve or bypass valve
to allow minimum flow.
5. For a single regulator, set the pilot to the
desired outlet (control) pressure according to
the Pilot Adjustment procedure.
For a wide-open downstream monitor
installation, adjust the upstream working
pilot until intermediate pressure is higher
than the desired setpoint of the monitor pilot.
Adjust the downstream monitoring pilot to
the desired monitoring takeover pressure.
Reduce the upstream pilot to the normal outlet
pressure setting.
For a wide-open upstream monitor
installation, adjust the downstream working
pilot to a setpoint higher than the setpoint of the
monitor pilot. Adjust the downstream monitoring
pilot to the desired monitoring takeover pressure.
Reduce the upstream pilot to the normal outlet
pressure setting.
For a working monitor installation, adjust
the setpoint of the upstream monitor pilot
to the desired maximum pressure. Adjust
the upstream working pilot to the desired
intermediate pressure setting. Adjust the
downstream pilot to a pressure setting slightly
above the upstream monitor pilot pressure
setting. Adjust the upstream monitor pilot to
its desired setpoint. Establish final desired
downstream pressure by adjusting the
downstream working regulator pilot.
6. After adjusting the pilot(s) to the desired pressure
setting(s), slowly open the downstream block
valve wide-open.
7. Close the bypass valve, if used.