Product Description
The ARMSTRONG 8as1270-243 is an EPDM O-ring designed for use in HVAC and fluid-handling assemblies where a reliable elastomeric seal is required. EPDM (ethylene propylene diene monomer) compound offers good resistance to water, steam, and many common HVAC system fluids, making it a practical choice for sealing applications in air handling and hydronic equipment. This O-ring measures 4.109 inches inner diameter with a 0.139-inch cross section, conforming to standard O-ring sizing conventions. It is typically installed by HVAC technicians and plumbers performing maintenance, repair, or component replacement on compatible Armstrong equipment.
This O-ring is suited for residential and light commercial HVAC applications, including air handler components and accessories within Armstrong product lines. It is commonly used when servicing assemblies that require a compression seal at a mating groove or port. The EPDM material is appropriate for moderate-temperature water and steam service typical of HVAC hydronic and air-side equipment. Technicians should verify groove dimensions match the 4.109-inch ID and 0.139-inch cross section before installation.
Key Features
- EPDM compound provides resistance to water, steam, and common HVAC system fluids
- 4.109-inch inner diameter suits standard large-bore O-ring grooves
- 0.139-inch cross section conforms to AS568 and equivalent sizing standards
- OEM Armstrong part for direct replacement in compatible assemblies
- Elastomeric construction allows uniform compression sealing in mating grooves
Compatibility
Designed as an OEM-style replacement O-ring for Armstrong HVAC room air parts and accessories assemblies requiring a 4.109-inch ID by 0.139-inch cross section EPDM seal.
Installation Notes
Installation should be performed by a qualified HVAC technician or plumber. Power down and depressurize the system before removing any components or existing seals. Inspect the mating groove for damage, debris, or corrosion before seating the new O-ring, and avoid using sharp tools that could nick the elastomer. Lightly lubricating the O-ring with a compatible grease prior to installation helps prevent tearing during assembly.
Technical Specifications
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Material: EPDM
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Inner Diameter: 4.109 inches
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Cross Section: 0.139 inches
Standard Information
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Brand: ARMSTRONG
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Manufacturer Part Number: 8as1270-243
