Blower Relief Valve Vacuum Capabilities Vacuum Preset Limit 122 in wc Outside Diameter 5 in Inlet Size 2 in Inlet Type NPT Compatible Manufacturer Part Number VFD41-H VFD41-L VFD41S VFD42-H VFD42-L VFZ601A-5W VFZ601A-7W VFZ701A-5W VFZ701A-7W Compatible Grainger Part Number 22NX88 22NX89 22NX90 22NX91 53WC11 53WC12 53WC13 53WC14 6JD24 Maximum Operating Pressure 28 in Hg Minimum Operating Pressure 1 in Hg Maximum Operating Temperature 400 Degrees F