PRV Control - Hydraulic fault-finding quick reference

We use the following terminology:

• P1 is the PRV Inlet pressure (also known as upstream pressure)
• P2 is the PRV Outlet pressure (also known as downstream pressure)
• P3 is the PRV Critical Point pressure (also known as CP pressure)
• PCS is the PRV Control Space Pressure (optional monitoring, not needed for control)

Attached is a quick reference guide for fault-finding common issues encountered when installing i2O APVs on PRVs. It describes how to investigate the following scenarios:

• High or increasing P2 Pressure
• Low or falling P2 Pressure
• PRV Oscillating at low flows
• Poor control of P2 pressure
• Varying P3 Pressure (not controlling with flow)
• P2 pressure too high at low flow, but controls OK at higher flows