Value Collection ZMSCHB90334 O-ring Backup Ring Nbr 90D

Product Description

The VALUE COLLECTION ZMSCHB90334 is a rectangular cross-section backup O-ring designed to prevent extrusion in high-pressure sealing applications. Manufactured from Nitrile Butadiene Rubber (NBR) with a 90 durometer hardness rating classified as extra hard, this ring measures 2.643 inches inner diameter by 3.009 inches outer diameter with a 0.0625-inch thickness. The 90 durometer compound resists deformation under load, making it well suited for hydraulic, pneumatic, and fluid system assemblies where standard O-rings require anti-extrusion support. Plumbers, HVAC technicians, and industrial maintenance professionals install backup rings alongside primary O-ring seals in grooved fittings and cylinder bores.

This backup ring is used in residential and commercial fluid systems where elevated pressure or temperature cycling would otherwise allow a primary O-ring to extrude past a clearance gap. The Dash 8-334 designation identifies the ring geometry within the standard sizing system, simplifying cross-reference and replacement sourcing. Typical installation scenarios include hydraulic cylinder rod seals, manifold face seals, and threaded port connections in plumbing and HVAC equipment exposed to a working temperature range of -40 to 250 degrees F. Sold in a package quantity of 10.

Key Features

• Rectangular cross-section profile functions as an anti-extrusion backup ring alongside primary O-ring seals
• NBR compound rated extra hard at 90 durometer for high-pressure resistance
• Working temperature range of -40 to 250 degrees F suits refrigerant, water, and hydraulic fluid service
• Dash 8-334 standard designation allows straightforward cross-reference and replacement identification
• Package quantity of 10 supports stocking for repeat service calls
• Weighs 0.02 pounds per unit; minimal bulk for field carry

Compatibility

Designed as an OEM-style replacement backup ring for fluid system assemblies requiring a Dash 8-334 rectangular cross-section seal with a 2.643-inch inner diameter and 3.009-inch outer diameter.

Installation Notes

Installation is performed by licensed plumbers, HVAC technicians, or qualified industrial maintenance personnel. Always depressurize and de-energize the system and drain fluid from the assembly before removing or installing seals. Backup rings are typically seated in the groove behind the primary O-ring on the low-pressure side; verify groove dimensions match the ring cross-section before assembly. Do not twist or stretch the ring during installation, as permanent deformation will compromise the seal.