• Direct-operated valves are used when loads are small and some downstream pressure droop may be accepted. They are generally used in light load services.
• Pilot-operated pressure reducing valves can respond quickly to varying load conditions while maintaining stable secondary pressure where precise pressure control is needed. They are generally intended for larger load applications.

Typical Applications in a Steam-Using Plant:

• Small load applications such as sterilizers, unit heaters, humidifiers, and small process equipment may typically use a simple Direct Acting PRV for pressure reduction.
• In case of larger flows, such as steam distribution piping, loads may fluctuate greatly depending on the operational status of the recipient equipment. Such load variations and large capacity would call for the use of a Pilot-operated PRV to reduce pressure.
• Furthermore, the amount of steam used by certain equipment at start-up may differ significantly from the amount required during normal operation. Such wide variations may also necessitate the use of a Pilot-operated PRV for pressure reduction.