Value Collection ZMSCH70350 O-ring Dash 350 Buna-n 70 Duro

Product Description

The VALUE COLLECTION ZMSCH70350 is a Dash 350 Buna-N (Nitrile Butadiene Rubber) O-ring with a round cross section, designed for static and dynamic sealing applications across HVAC, plumbing, hydraulic, and pneumatic systems. It measures 4.625 inches inside diameter, 5 inches outside diameter, and 0.1875 inches (3/16 inches) thick. The compound carries a Shore A hardness of 70, placing it in the hard hardness rating category. Buna-N is the most widely used O-ring elastomer in the trades, valued for its excellent resistance to petroleum-based fluids, strong compression set performance, and solid tear and abrasion resistance.

This O-ring suits applications where the sealing element contacts petroleum products, oils, fuels, hydraulic fluids, and many common refrigeration lubricants. Typical install scenarios include pump shaft seals, valve body seals, compressor service ports, and fluid line fittings in both residential and light commercial systems. The temperature range of -40 degrees F to 250 degrees F covers most ambient and process conditions found in HVAC, plumbing, and general mechanical service work. Each package contains 5 pieces.

Key Features

• Buna-N compound with excellent resistance to petroleum products, oils, and hydraulic fluids
• Shore A 70 hardness provides a firm seal with reliable compression set performance
• Rated for service from -40 degrees F to 250 degrees F
• Round cross section in standard Dash 350 sizing for broad interchange compatibility
• Tear and abrasion resistant for dynamic sealing applications
• Meets SAE and MIL-Spec standards

Compatibility

Designed as a standard Dash 350 O-ring replacement compatible with sealing grooves machined to SAE and MIL-Spec Dash 350 dimensional standards in HVAC, plumbing, hydraulic, and pneumatic equipment. Not recommended for exposure to ozone, direct sunlight during storage, or contact with electrical equipment generating ozone. Not FDA approved.

Installation Notes

O-ring replacement is performed by licensed HVAC technicians, plumbers, and mechanical technicians depending on the system type. Always depressurize and isolate the circuit before disassembly, and confirm the sealing groove is clean and free of damage prior to installation. Apply a light coat of a compatible lubricant to ease installation and prevent rolling or twisting of the ring. Store unused O-rings away from direct sunlight, ozone sources, and electrical equipment to preserve elastomer integrity.