As stated in REGO’s Warning Document…
Simply retesting pressure relief valves manufactured by RegO that have been in service for several years to confirm conformance with start-to-discharge and reseal ranges does NOT guarantee that the valve is suitable for continued service. Or that the valve will perform as designed at nominal pressures or in emergency conditions. The environment in which the pressure relief valve has been exposed, the age and the physical condition of the valve body, seat disc, and components; all play a critical role in the life of a relief valve and its ability to perform as designed. Please see the attached inspection, replacement, and warning guidelines from us.