Visual Inspection: Examining the physical condition of the valve body, isolation valves, and line strainers for corrosion or debris accumulation.
Differential Pressure Testing: utilizing calibrated gauge equipment to measure the pressure drop across the check valves and the relief valve opening point.
Hazard Rating Verification: Confirming that the installed device type matched the current hazard rating of the commercial kitchen.
The Repair Process
Device Selection and Replacement: The obsolete unit was replaced with a Reduced Pressure Zone (RPZ) device. The RPZ configuration is the industry standard for high-hazard protection because it features two independent check valves and a hydraulically operated differential relief valve. This design ensures that even if both checks fail, the relief valve will discharge water to the atmosphere, preventing backflow. You can examine the specific mechanics of RPZ valves here.
Precision Installation: The installation process involved reconfiguring the pipework to ensure adequate clearance for maintenance and visibility. Strainers were installed upstream to protect the valve internals from debris, a common cause of device failure in older commercial districts.
Commissioning and Testing: Post-installation, the new RPZ valve underwent rigorous commissioning. This involved a certified functional test to verify that the opening differential of the relief valve and the tightness of the check valves met manufacturer and utility specifications.
