Value Collection ZMSCS70345 Silicone O-ring Dash 345 5-pack

Product Description

The VALUE COLLECTION ZMSCS70345 is a round-cross-section silicone O-ring designed for static and dynamic sealing applications across HVAC, plumbing, and industrial fluid systems. It measures 4 inches inside diameter, 4-3/8 inches outside diameter, and 3/16 inches thick, conforming to Dash 345 dimensions. Rated for a working temperature range of -80 degrees F to 450 degrees F, this O-ring is well suited for systems that cycle through extreme heat or cold. The silicone compound provides good dry heat resistance, weather resistance, and ozone resistance. Each package contains 5 O-rings. Hardness is rated at 70 Shore A, placing it in the hard hardness category.

This O-ring is used in residential and commercial HVAC equipment, plumbing assemblies, pump housings, and general industrial applications where a reliable seal against oils, chemicals, and solvents is required. It is particularly appropriate for installations demanding a wide service temperature range, such as high-efficiency furnace flue connections, water treatment components, and chemical handling systems. The white silicone construction is compatible with a broad range of fluid media, though oil resistance is limited and should be evaluated against the specific application before installation.

Key Features

• Dash 345 standard dimensions: 4 inches ID, 4-3/8 inches OD, 3/16 inches thick
• Wide service temperature range: -80 degrees F to 450 degrees F
• 70 Shore A hardness for firm, consistent sealing compression
• Good resistance to dry heat, weather, and ozone
• Compatible with oils, chemicals, and solvents — note limited oil resistance
• Sold in a pack of 5 to support stocking and repeat service calls

Compatibility

Designed as a standard Dash 345 replacement O-ring for any application requiring a 4-inch ID silicone seal with a round cross section and 3/16-inch thickness.

Installation Notes

O-ring installation should be performed by a qualified technician familiar with the host system — HVAC, plumbing, or mechanical as applicable. Shut down and de-pressurize the system completely before removing the existing O-ring. Inspect the groove and mating surfaces for damage, scoring, or debris before seating the replacement. Do not overstretch or twist the O-ring during installation, as this can compromise the seal integrity.