Description
The Armstrong S-35 Lead-Free Bronze In-Line Circulator Pump is a professional-grade solution engineered for demanding hydronic heating and cooling applications, as well as potable domestic water systems. Its NSF 372-certified, lead-free bronze body ensures full compliance with lead-free regulations, making it a trusted choice for both commercial and residential installations where water safety is a priority. The robust three-piece design simplifies on-site servicing and reduces downtime, while the mechanical seal delivers consistent, leak-free performance over the life of the system. Powered by a single-phase, 115 VAC motor running at 1,800 RPM, the S-35 provides a maximum flow rate of 75 GPM with up to 11 ft of head — offering the hydraulic capacity needed for medium to large circulating systems. A resilient motor mount minimizes vibration and noise, contributing to quieter system operation. Rated for temperatures up to 225°F and pressures up to 125 PSIG, this pump is built to perform reliably across a wide range of system conditions. The 2-inch NPT inline connection allows for straightforward integration into existing piping without complex retrofitting. Whether you’re outfitting a new hydronic system or upgrading an aging circulator, the Armstrong S-35 delivers the durability, efficiency, and code compliance that HVAC and plumbing professionals demand.
Key Features:
- Lead-free bronze construction — NSF 372 certified for potable water compliance
- Three-piece serviceable design for fast, cost-effective maintenance
- Mechanical seal for long-lasting, leak-free operation
- 75 GPM max flow rate with 11 ft maximum head
- Rated to 225°F and 125 PSIG for versatile system compatibility
- Single-phase, 115 VAC / 1,800 RPM motor for dependable, efficient performance
- 2-inch NPT inline connections for easy installation
- Suitable for hydronic heating and cooling and domestic water systems
Technical Specifications:
- HP Rating: 1/6 HP
- Flow Rate: 75 GPM
- Maximum Head: 11 ft
- Connection Size: 2 in NPT
- Voltage: 115 VAC
- Phase: 1-Phase
- Motor Speed: 1,800 RPM
- Temperature Rating: 225°F
- Pressure Rating: 125 PSIG
- Body Material: Lead-Free Bronze
- Dimensions: 15 in W x 13.38 in H
- Certifications: NSF 372







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