Description
Armstrong S-57-1 Bronze Pump with ECM Motor | Ultimate Product Guide
The Armstrong 106285MF-843, model S-57-1, is a high-efficiency, all-bronze circulator pump engineered for both performance and significant energy savings. This model is distinguished by its advanced 3/4 HP, 230V ECM (Electronically Commutated Motor), which automatically adjusts speed to match system demand, reducing electricity consumption by up to 80% compared to fixed-speed pumps.
Construct entirely with corrosion-resistant bronze, this pump is perfectly safe for potable (drinking) water systems and durable enough for closed-loop hydronic applications. As part of Armstrong’s trusted Series S line, the S-57-1 combines the reliability of a time-tested mechanical design with the intelligence and efficiency of modern motor technology, making it an ideal choice for eco-conscious homeowners and professionals modernizing residential and light commercial systems.
Detailed Technical Specifications
| Feature | Specification |
|---|---|
| Manufacturer | Armstrong Pumps |
| Series | Series S |
| Part Number | 106285MF-843 |
| Model | S-57-1 |
| Pump Type | In-Line Circulator |
| Horsepower (HP) | 3/4 HP |
| Motor Technology | ECM (Electronically Commutated Motor) |
| Voltage | 230V |
| Phase | Single Phase |
| Construction | All Bronze (Potable Water Safe) |
| Connection Type | Flanged (Standard for S-57) |
| Control | Automatic, Self-Adjusting Speed |
Note: For precise performance specs (GPM, Head), consult the official Armstrong performance curve for this model.
Key Features & Benefits
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ECM Motor Technology: Dramatically reduces energy consumption by adjusting speed to actual load, not running at full speed constantly.
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All-Bronze Construction: Certified for potable water applications and provides excellent longevity in various water conditions.
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Automatic Operation: Self-regulating; no manual speed settings or external controls are needed for basic operation.
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High Efficiency: Exceeds DOE energy regulations and provides significant cost savings on utility bills.
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Quiet Operation: ECM motors and precision hydraulic design result in exceptionally low noise levels.
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Flanged Connections: Ensure a robust, leak-free seal for a secure installation.
Armstrong ECM vs. Standard PSC Pumps: Comparison Table
This table highlights the revolutionary efficiency of the ECM motor.
| Feature | Armstrong S-57-1 (ECM) | Standard Fixed-Speed Pump (PSC) |
|---|---|---|
| Motor Technology | ECM (Variable Speed) | PSC (Permanent Split Capacitor) |
| Energy Consumption | Up to 80% Less | High (Constant Full Speed) |
| Operation | Self-Adjusting to Demand | Fixed Speed, Constant Flow |
| Noise Level | Whisper Quiet | Moderate to Loud |
| Power Requirement | 230V | 115V or 230V |
| Initial Cost | Higher | Lower |
| Lifecycle Cost | Lowest (Savings on Energy) | Higher |
| Best For | Energy Efficiency, Modern Systems | Basic Replacement, Low Budget |
Frequently Asked Questions (FAQ)
Q1: How does the ECM motor save energy?
A: Unlike a standard motor that runs at full speed whenever it’s on, an ECM motor senses the system’s pressure requirements (the “load”). It automatically ramps its speed up or down to deliver exactly the needed flow, using only the minimum energy required. This eliminates the energy waste of constant full-speed operation.
Q2: Is this pump definitely safe for drinking water?
A: Yes, absolutely. The all-bronze construction is the key feature that makes this pump completely safe and approved for use in potable (drinking) water systems. It will not rust or contaminate the water supply.
Q3: Do I need a special controller for the ECM motor?
A: For this model, no. It is a “plug-and-play” ECM pump. The motor itself contains the intelligence to self-adjust based on system demand. More advanced external controllers are available for custom settings but are not required for basic, efficient operation.
Q4: Why is a 230V motor used?
A: 230V operation is more efficient for motors of this size. It allows the motor to draw fewer amps for the same power output, which reduces electrical stress and heat generation, contributing to longer motor life and efficiency.
Q5: What are typical applications for this pump?
A: This pump is incredibly versatile due to its bronze construction and efficient motor:
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Domestic Hot Water Recirculation Loops
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Potable Water Pressure Boosting
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Residential and Light Commercial Hydronic Heating Systems
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Snow Melt Systems
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Solar Thermal Systems
Q6: Are the flanges included?
A: The product name (S-57-1) indicates a flanged connection. Typically, Armstrong circulators are sold as a complete unit with flanges attached. However, it is always best to confirm what is included in the specific package with your supplier.
Pros and Cons
Pros:
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Massive Energy Savings: The ECM technology can reduce pumping electricity costs by up to 80%, offering a rapid return on investment.
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Potable Water Safe: All-bronze construction is ideal for drinking water applications.
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Exceptially Quiet: Significantly quieter than standard fixed-speed circulators.
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Automatic Optimization: Continuously self-adjusts for optimal performance without user intervention.
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Environmentally Friendly: Reduced energy consumption lowers the carbon footprint.
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Proven Armstrong Quality: Built by a respected and established name in pumping.
Cons:
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Higher Initial Cost: The advanced ECM technology comes with a higher upfront price tag.
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230V Power Requirement: Requires a 230V circuit, which may not be available in all locations where a 115V circuit is present.
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Electronic Complexity: The internal electronics can be more costly to repair than a simple PSC motor if they fail out of warranty.
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Potential Compatibility: In very old systems with high flow resistance, ensure the pump can achieve the required minimum flow.
Conclusion & Best Applications
The Armstrong 106285MF-843 S-57-1 is a forward-thinking pump that prioritizes lifetime operating cost over initial purchase price. It is the perfect choice for modern installations and retrofits where energy efficiency, material safety, and quiet operation are paramount.
You should choose this pump if:
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You are replacing an old circulator and want to significantly reduce your energy bills.
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You need a pump for a domestic drinking water application.
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Quiet operation is important, especially in living spaces.
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You are designing a new, efficient home or upgrading a system for sustainability.
For homeowners and professionals looking to invest in efficiency and performance, the Armstrong ECM circulator is a superior and smart choice.
Disclaimer: Professional installation is recommended to ensure proper wiring (230V), piping support, and system operation. Always confirm the pump’s performance curve matches your system’s requirements. For potable water applications, ensure all installed components are certified for drinking water use.







