Type EZL TYPE 67C PILOT SUPPLY REGULATOR
P590 SERIES PILOT SUPPLY FILTER TYPE 6352 PILOT
TYPE 6352 PILOT
INLET PRESSURE
P590 SERIES PILOT SUPPLY FILTER
TYPE EZL MAIN VALVE
TYPE EZL MAIN VALVE
OUTLET PRESSURE LOADING PRESSURE INTERMEDIATE PRESSURE ATMOSPHERIC PRESSURE E0948
Figure 4. Wide-Open Monitoring System
Working Monitoring Regulators (figure 5) In a working monitoring system, the upstream regulator requires two pilots and it is always the monitoring regulator. The additional pilot permits the monitoring regulator to act as a series regulator to control an intermediate pressure during normal operation. In this way, both units are always operating and can be easily checked for proper operation. In normal operation, the working regulator controls the outlet pressure of the system. The monitoring regulator’s working pilot controls the intermediate pressure and the monitoring pilot senses the system’s outlet pressure. If the working regulator fails, the monitoring pilot will sense the increase in outlet pressure and take control. Note The working regulator must be rated for the maximum allowable operating
pressure of the system because this will be its inlet pressure if the monitoring regulator fails. Also, the outlet pressure rating of the monitoring pilot, and any other components that are exposed to the intermediate pressure must be rated for full inlet pressure. Working monitor installations require a Type EZL main valve with a working pilot and a monitoring pilot for the upstream regulator and a Type EZL with the appropriate pilot for the downstream regulator.
Adjustment Adjusting the monitor regulator is similar to adjusting the main regulator. Monitor setpoints are set slightly higher than the main regulator. However, the value of this difference cannot be determined in advance, as it depends on the particular characteristics of each application.
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