Product Overview
For dependable performance in residential and light commercial hydronic systems, the Armstrong 106284MF-136A S-55-3 circulator sets the standard. This versatile 1/2 HP pump is engineered to efficiently move hot water or glycol solutions through heating systems, radiant floor loops, and domestic hot water recirculation applications. Its robust construction and thoughtful design make it a go-to choice for HVAC contractors and plumbing professionals seeking a balance of performance and value.
The pump features a durable cast iron body and a corrosion-resistant bronze impeller, ensuring long service life in closed-loop systems. The energy-efficient, wet-rotor design operates quietly while minimizing power consumption. With three manual speed settings, installers can easily fine-tune the pump’s performance to match specific system requirements, optimizing flow and head pressure for maximum efficiency. For help with selection, read our guide on [How to Size a Circulator Pump for Home Heating Systems].
As part of Armstrong’s respected S-55 series, this model continues a legacy of reliability that professionals have trusted for decades. Whether you’re replacing a failed circulator or installing a new system, this pump delivers the consistent performance needed to keep comfort systems running smoothly. Learn more about its place in modern hydronics in our article [The Evolution of Residential Circulator Pumps].
Technical Specifications
| Specification | Details |
|---|---|
| Model | Armstrong S-55-3 (106284MF-136A) |
| Motor Power | 1/2 HP (0.37 kW) |
| Connection Size | 1-1/4″ Flange x 1-1/4″ Flange |
| Impeller Material | Bronze |
| Housing Material | Cast Iron |
| Max Head | 32 ft (9.8 m) |
| Max Flow | 100 US gpm (378 L/min) |
| Speed Settings | 3-Speed (Manual) |
| Max Operating Pressure | 125 psi (8.6 bar) |
| Max Fluid Temperature | 230°F (110°C) |
| Voltage | 115V, 1-Phase |
| NPSH Required | 2.5 ft (0.76 m) |
Comparison Table: Armstrong S-55-3 vs. Alternative Pumps
| Feature | Armstrong S-55-3 1/2 HP | Competitor A (Basic Circulator) | Competitor B (High-Efficiency Model) |
|---|---|---|---|
| Design & Value | Professional Grade, Competitive Price | Economy Grade | Premium Price |
| Energy Efficiency | Good (Wet-Rotor Design) | Standard | Excellent (ECM Motor) |
| Speed Control | 3-Speed Manual | Often Single-Speed | Variable Speed |
| Material Durability | Cast Iron/Bronze | May use composite materials | Cast Iron/Bronze |
| Application Range | Residential & Light Commercial | Residential Only | Residential & Commercial |
| Installation | Standard Flange Connections | Standard Flange Connections | May require special fittings |
Frequently Asked Questions (FAQs)
Q1: Is this pump suitable for both hot water heating systems and chilled water applications?
Yes, the Armstrong S-55-3 is designed for closed-loop hydronic systems and works effectively in both heating and cooling applications, provided the system parameters fall within the pump’s published performance curve and temperature ratings.
Q2: What are the main advantages of the 3-speed setting?
The three-speed capability (high, medium, low) allows for performance adjustment after installation. If a system has too much or too little flow, the speed can be changed to better match the system’s requirements without replacing components, saving time and money on callbacks.
Q3: Can this pump be used with antifreeze in the system?
Yes, it can handle glycol solutions used for freeze protection. However, glycol increases the fluid’s viscosity, which reduces pump performance. The system designer should apply appropriate correction factors to ensure adequate pump sizing. For more details, see our technical bulletin [System Performance with Glycol Solutions].
Q4: How does this wet-rotor circulator compare to a traditional circulator with a coupling?
Wet-rotor designs are lubricated and cooled by the system fluid, making them typically quieter and requiring no external lubrication. They are generally more compact and have fewer maintenance requirements than traditional coupled pumps, which need periodic lubrication and can suffer from coupling failures.
Q5: What is the typical lifespan of this circulator?
With proper installation and a clean system, the Armstrong S-55-3 can provide 10-15 years of reliable service. The lifespan is heavily dependent on water quality and system maintenance. For larger residential applications, you might also consider the [Armstrong 1 HP S-55-5 Circulator].
Pros and Cons
| Pros | Cons |
|---|---|
| Proven Reliability from a trusted brand | Manual Speed Setting requires physical adjustment |
| Energy-Efficient Operation with wet-rotor design | Not Self-Priming – requires flooded suction installation |
| 3-Speed Flexibility for system balancing | Cast Iron Construction is susceptible to rust if not properly maintained |
| Compact Design for easy installation in tight spaces | Standard Efficiency compared to modern ECM-driven pumps |
| Durable Construction with cast iron body and bronze impeller | Limited to Clean Water applications – not for dirty water or pools |
Conclusion & Ideal Use Cases
The Armstrong 106284MF-136A S-55-3 1/2 HP circulator represents an excellent value proposition for standard-efficiency applications where reliability and serviceability are paramount. It hits the sweet spot for residential hydronic systems and light commercial applications that don’t require the advanced features of premium-priced models.
This pump is ideally suited for:
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Residential Hydronic Heating: Boiler loop circulation for baseboard, radiator, and radiant floor systems.
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Domestic Hot Water Recirculation: Maintaining hot water availability at fixtures.
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Snow Melt Systems: Circulating heated glycol solutions for driveway and walkway snow melt.
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Light Commercial Applications: Small office buildings, retail spaces, and multi-family housing hydronic systems.
For basic residential replacement needs, this pump offers superior performance to economy models, while for applications demanding maximum efficiency, consider Armstrong’s [ECM High-Efficiency Circulator] line. The S-55-3 remains a workhorse in the HVAC industry, backed by Armstrong’s strong reputation. For comprehensive performance data and industry standards, consult the Hydraulic Institute’s website (External Link).
Contact our product specialists for assistance matching this pump to your specific application or to discuss your project requirements.
