Value Collection ZMSCH90344 O-ring Dash 344 Nbr 90 Duro 25pk

Product Description

The VALUE COLLECTION ZMSCH90344 is a Dash 344 Nitrile Butadiene Rubber (NBR/Buna-N) O-ring rated at 90 durometer for extra-hard sealing applications. It measures 3.875 inches inside diameter, 4.25 inches outside diameter, and 0.1875 inches thick with a round cross section. Rated for continuous service from -40 to 250 degrees F, this O-ring is engineered for strong resistance to petroleum-based fluids, making it a dependable choice in hydraulic, pneumatic, and fluid-handling assemblies. HVAC technicians, plumbers, and industrial mechanics regularly specify Buna-N seals at this hardness for high-compression, oil-exposed connection points. Each package contains 25 pieces. Meets SAE and MIL-Spec standards.

This O-ring is appropriate for residential and commercial applications wherever a Dash 344 NBR seal is called out, including pump housings, valve bodies, pipe flanges, filter housings, and refrigeration service fittings that contact petroleum products. The 90-durometer rating provides extra hardness suited to high-pressure connections with tight tolerances. Its temperature range covers most HVAC and plumbing operating conditions without seal degradation. Compatible with petroleum products; not suitable for contact with ozone, sunlight exposure during storage, or environments that generate ozone from motors or electrical equipment.

Key Features

• Buna-N (NBR) elastomer — excellent resistance to petroleum-based fluids and lubricants
• 90 durometer (extra-hard) for high-compression sealing at tight-tolerance joints
• Operating range of -40 to 250 degrees F for broad HVAC and plumbing serviceability
• Round cross section, 0.1875 inches thick — conforms to Dash 344 industry sizing
• Meets SAE and MIL-Spec standards
• Sold in a package of 25 pieces to support service stock and multi-unit jobs

Compatibility

Designed as a Dash 344 O-ring replacement for any assembly specifying a 3.875-inch ID, 4.25-inch OD, 0.1875-inch-thick NBR seal. Compatible with petroleum products. Not recommended for use with ozone-generating environments or prolonged direct sunlight exposure during storage.

Installation Notes

Installation is typically performed by licensed HVAC technicians, plumbers, or industrial mechanics. Always depressurize and isolate the system before removing the existing seal and seating the replacement O-ring. Inspect the groove and mating surfaces for nicks or corrosion that could cause leakage, and apply a compatible lubricant to the O-ring before installation to prevent rolling or tearing during assembly. Do not store Buna-N O-rings near motors, ozone-generating equipment, or in direct sunlight, as ozone and UV exposure accelerate elastomer degradation.