Most Fuji Ring Compressors should not be operated in a "dead-head" condition. These relief valves are designed to protect the blowers from overheating when operating dead-headed under vacumm. The valves are preset to provide the proper protection for the appropriate model, which is approximately 90% of the dead-head vacuum and is adjustable to a lower setting.
Connection 2.5" (f) NPT
Preset at minimum air flow or maximum pressure/vacuum level
Valves protect regenerative blowers from overheating