Value Collection ZMSCH70348 O-ring Dash 348 Nbr 70 5-pack

Product Description

The VALUE COLLECTION ZMSCH70348 is a Dash 348 Nitrile Butadiene Rubber (NBR/Buna-N) O-ring with a round cross section, sized at 4.375 inches inside diameter, 4.750 inches outside diameter, and 0.1875 inches thick. Rated at 70 Shore A hardness, this O-ring is engineered for static and dynamic sealing applications involving petroleum-based fluids. It performs across a working temperature range of -40 degrees F to 250 degrees F, making it suitable for a broad range of HVAC, plumbing, and fluid-handling systems. Each order includes a package of 5 O-rings. Licensed HVAC technicians, pipefitters, and plumbers specify Buna-N rings for their excellent resistance to petroleum products, compression set stability, and tear and abrasion resistance.

This O-ring is used in residential and commercial applications where seals must resist petroleum-based lubricants, oils, fuels, and hydraulic fluids. Typical install scenarios include pump assemblies, valve bodies, pipe couplings, refrigerant line fittings, and fluid-system manifolds. The Dash 348 designation follows the AS568 standard sizing system, allowing straightforward cross-referencing during maintenance and repair. This size is commonly found in larger-diameter pipe and equipment flanges. This part should not be stored in direct sunlight or near motors or other electrical equipment that may generate ozone, as ozone degrades NBR elastomers over time.

Key Features

• Buna-N (NBR) elastomer — the most widely used O-ring material for petroleum-product compatibility
• 70 Shore A hardness rating provides a balance of flexibility and compression resistance
• Operating range of -40 degrees F to 250 degrees F suits most HVAC and plumbing service conditions
• Round cross section and Dash 348 designation for straightforward AS568-standard replacement
• Meets SAE and MIL-Spec standards
• Sold in a package of 5 for service truck stocking and repeat maintenance tasks

Compatibility

Designed as a standard AS568 Dash 348 replacement O-ring compatible with petroleum-based fluid systems. Suitable for use with petroleum products including oils, fuels, and hydraulic fluids. Not recommended for applications involving ozone, strong acids, ketones, or esters.

Installation Notes

Installation is typically performed by licensed plumbers, pipefitters, or HVAC technicians during valve, pump, or flange service. Always depressurize and drain the system before removing or replacing any O-ring seal. Lightly lubricate the O-ring with a compatible petroleum-based lubricant before seating to prevent tearing during installation. Inspect the groove and mating surfaces for scoring or debris before installing the new ring.