Value Collection ZMSCHB90212 Nbr O-ring Backup Ring 50pk

Product Description

The VALUE COLLECTION ZMSCHB90212 is a Dash 8-212 nitrile butadiene rubber (NBR) backup O-ring with a rectangular cross section, designed for static and low-cycle dynamic sealing applications. It measures 0.891 inches inner diameter, 1.125 inches outer diameter, and 0.0468 inches thick. Rated at 90 durometer (extra hard), it resists extrusion under pressure and maintains a reliable seal across a temperature range of -40 to 250 degrees F. Each package contains 50 rings. NBR construction provides good resistance to petroleum-based fluids, hydraulic oils, and common refrigerants, making it a standard choice for HVAC, plumbing, and fluid-handling service work.

This backup ring is suited for use in hydraulic cylinders, pneumatic fittings, valve assemblies, refrigerant service ports, and other pressurized fluid connections where a standard O-ring alone may not prevent extrusion. The rectangular profile seats against a primary O-ring to block gap extrusion in high-pressure or high-clearance grooves. Typical applications include residential and light commercial HVAC equipment, plumbing valve assemblies, and general fluid-system maintenance. The 50-unit pack suits shop stock or service van inventory for techs who encounter this dash size regularly.

Key Features

• Dash 8-212 designation: 0.891 inches ID, 1.125 inches OD, 0.0468 inches thick
• 90 durometer extra-hard NBR resists extrusion at elevated pressure
• Rectangular cross section functions as a backup ring alongside a primary O-ring
• Temperature rated from -40 to 250 degrees F for broad service compatibility
• NBR material compatible with petroleum oils, hydraulic fluids, and common refrigerants
• 50-ring pack supports shop stock and fleet service van replenishment

Compatibility

Designed as an OEM-style replacement backup ring for any system or assembly that specifies a Dash 8-212 rectangular-profile NBR ring. Note: this product is not FDA approved and should not be used in potable water or food-contact applications.

Installation Notes

Installation is typically performed by licensed HVAC technicians, plumbers, or hydraulic system technicians. Always depressurize and isolate the system before removing existing seals, and follow applicable IPC or IFGC guidelines for the system being serviced. Inspect the groove and mating surfaces for nicks or corrosion before seating the new ring. Lubricate the ring with a fluid compatible with both the ring material and the system media before assembly to prevent tearing or rolling during installation.