{"product_id":"armstrong-106284mf-136a-s-55-3-pump-1-2-hp-cast-iron-circulator-hvac-hydronic-systems","title":"Armstrong 106284MF-136A S-55-3 Pump | 1\/2 HP Cast Iron Circulator | HVAC \u0026 Hydronic Systems","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e \u003cp class=\"ds-markdown-paragraph\"\u003eFor 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.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003eThe 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 \u003cstrong\u003e[How to Size a Circulator Pump for Home Heating Systems]\u003c\/strong\u003e.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003eAs 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 \u003cstrong\u003e[The Evolution of Residential Circulator Pumps]\u003c\/strong\u003e.\u003c\/p\u003e \u003chr\u003e \u003ch3\u003e\u003cstrong\u003eTechnical Specifications\u003c\/strong\u003e\u003c\/h3\u003e \u003cdiv class=\"ds-scroll-area _1210dd7\"\u003e \u003cdiv class=\"ds-scroll-area__gutters\"\u003e \u003cdiv class=\"ds-scroll-area__horizontal-gutter\"\u003e\u003c\/div\u003e \u003cdiv class=\"ds-scroll-area__vertical-gutter\"\u003e\u003c\/div\u003e \u003c\/div\u003e \u003ctable\u003e \u003cthead\u003e \u003ctr\u003e \u003cth\u003eSpecification\u003c\/th\u003e \u003cth\u003eDetails\u003c\/th\u003e \u003c\/tr\u003e \u003c\/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eModel\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eArmstrong S-55-3 (106284MF-136A)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMotor Power\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e1\/2 HP (0.37 kW)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eConnection Size\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e1-1\/4″ Flange x 1-1\/4″ Flange\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eImpeller Material\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eBronze\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eHousing Material\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eCast Iron\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMax Head\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e32 ft (9.8 m)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMax Flow\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e100 US gpm (378 L\/min)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eSpeed Settings\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e3-Speed (Manual)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMax Operating Pressure\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e125 psi (8.6 bar)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMax Fluid Temperature\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e230°F (110°C)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e115V, 1-Phase\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eNPSH Required\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e2.5 ft (0.76 m)\u003c\/td\u003e \u003c\/tr\u003e \u003c\/tbody\u003e \u003c\/table\u003e \u003c\/div\u003e \u003chr\u003e \u003ch3\u003e\u003cstrong\u003eComparison Table: Armstrong S-55-3 vs. Alternative Pumps\u003c\/strong\u003e\u003c\/h3\u003e \u003cdiv class=\"ds-scroll-area _1210dd7\"\u003e \u003cdiv class=\"ds-scroll-area__gutters\"\u003e \u003cdiv class=\"ds-scroll-area__horizontal-gutter\"\u003e \u003cdiv class=\"ds-scroll-area__horizontal-bar\"\u003e\u003c\/div\u003e \u003c\/div\u003e \u003cdiv class=\"ds-scroll-area__vertical-gutter\"\u003e\u003c\/div\u003e \u003c\/div\u003e \u003ctable\u003e \u003cthead\u003e \u003ctr\u003e \u003cth\u003eFeature\u003c\/th\u003e \u003cth\u003eArmstrong S-55-3 1\/2 HP\u003c\/th\u003e \u003cth\u003eCompetitor A (Basic Circulator)\u003c\/th\u003e \u003cth\u003eCompetitor B (High-Efficiency Model)\u003c\/th\u003e \u003c\/tr\u003e \u003c\/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eDesign \u0026amp; Value\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003eProfessional Grade, Competitive Price\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eEconomy Grade\u003c\/td\u003e \u003ctd\u003ePremium Price\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eEnergy Efficiency\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003eGood (Wet-Rotor Design)\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eStandard\u003c\/td\u003e \u003ctd\u003eExcellent (ECM Motor)\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eSpeed Control\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003e3-Speed Manual\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eOften Single-Speed\u003c\/td\u003e \u003ctd\u003eVariable Speed\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eMaterial Durability\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003eCast Iron\/Bronze\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eMay use composite materials\u003c\/td\u003e \u003ctd\u003eCast Iron\/Bronze\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eApplication Range\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003eResidential \u0026amp; Light Commercial\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eResidential Only\u003c\/td\u003e \u003ctd\u003eResidential \u0026amp; Commercial\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\u003cstrong\u003eInstallation\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003e\u003cstrong\u003eStandard Flange Connections\u003c\/strong\u003e\u003c\/td\u003e \u003ctd\u003eStandard Flange Connections\u003c\/td\u003e \u003ctd\u003eMay require special fittings\u003c\/td\u003e \u003c\/tr\u003e \u003c\/tbody\u003e \u003c\/table\u003e \u003c\/div\u003e \u003chr\u003e \u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions (FAQs)\u003c\/strong\u003e\u003c\/h3\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eQ1: Is this pump suitable for both hot water heating systems and chilled water applications?\u003c\/strong\u003e\u003cbr\u003e 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.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eQ2: What are the main advantages of the 3-speed setting?\u003c\/strong\u003e\u003cbr\u003e 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.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eQ3: Can this pump be used with antifreeze in the system?\u003c\/strong\u003e\u003cbr\u003e 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 \u003cstrong\u003e[System Performance with Glycol Solutions]\u003c\/strong\u003e.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eQ4: How does this wet-rotor circulator compare to a traditional circulator with a coupling?\u003c\/strong\u003e\u003cbr\u003e 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.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eQ5: What is the typical lifespan of this circulator?\u003c\/strong\u003e\u003cbr\u003e 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 \u003cstrong\u003e[Armstrong 1 HP S-55-5 Circulator]\u003c\/strong\u003e.\u003c\/p\u003e \u003chr\u003e \u003ch3\u003e\u003cstrong\u003ePros and Cons\u003c\/strong\u003e\u003c\/h3\u003e \u003cdiv class=\"ds-scroll-area _1210dd7\"\u003e \u003cdiv class=\"ds-scroll-area__gutters\"\u003e \u003cdiv class=\"ds-scroll-area__horizontal-gutter\"\u003e \u003cdiv class=\"ds-scroll-area__horizontal-bar\"\u003e\u003c\/div\u003e \u003c\/div\u003e \u003cdiv class=\"ds-scroll-area__vertical-gutter\"\u003e\u003c\/div\u003e \u003c\/div\u003e \u003ctable\u003e \u003cthead\u003e \u003ctr\u003e \u003cth\u003ePros\u003c\/th\u003e \u003cth\u003eCons\u003c\/th\u003e \u003c\/tr\u003e \u003c\/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd\u003e\n\u003cstrong\u003eProven Reliability\u003c\/strong\u003e from a trusted brand\u003c\/td\u003e \u003ctd\u003e\n\u003cstrong\u003eManual Speed Setting\u003c\/strong\u003e requires physical adjustment\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\n\u003cstrong\u003eEnergy-Efficient Operation\u003c\/strong\u003e with wet-rotor design\u003c\/td\u003e \u003ctd\u003e\n\u003cstrong\u003eNot Self-Priming\u003c\/strong\u003e – requires flooded suction installation\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\n\u003cstrong\u003e3-Speed Flexibility\u003c\/strong\u003e for system balancing\u003c\/td\u003e \u003ctd\u003e\n\u003cstrong\u003eCast Iron Construction\u003c\/strong\u003e is susceptible to rust if not properly maintained\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\n\u003cstrong\u003eCompact Design\u003c\/strong\u003e for easy installation in tight spaces\u003c\/td\u003e \u003ctd\u003e\n\u003cstrong\u003eStandard Efficiency\u003c\/strong\u003e compared to modern ECM-driven pumps\u003c\/td\u003e \u003c\/tr\u003e \u003ctr\u003e \u003ctd\u003e\n\u003cstrong\u003eDurable Construction\u003c\/strong\u003e with cast iron body and bronze impeller\u003c\/td\u003e \u003ctd\u003e\n\u003cstrong\u003eLimited to Clean Water\u003c\/strong\u003e applications – not for dirty water or pools\u003c\/td\u003e \u003c\/tr\u003e \u003c\/tbody\u003e \u003c\/table\u003e \u003c\/div\u003e \u003chr\u003e \u003ch3\u003e\u003cstrong\u003eConclusion \u0026amp; Ideal Use Cases\u003c\/strong\u003e\u003c\/h3\u003e \u003cp class=\"ds-markdown-paragraph\"\u003eThe 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.\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eThis pump is ideally suited for:\u003c\/strong\u003e\u003c\/p\u003e \u003cul\u003e \u003cli\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eResidential Hydronic Heating:\u003c\/strong\u003e Boiler loop circulation for baseboard, radiator, and radiant floor systems.\u003c\/p\u003e \u003c\/li\u003e \u003cli\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eDomestic Hot Water Recirculation:\u003c\/strong\u003e Maintaining hot water availability at fixtures.\u003c\/p\u003e \u003c\/li\u003e \u003cli\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eSnow Melt Systems:\u003c\/strong\u003e Circulating heated glycol solutions for driveway and walkway snow melt.\u003c\/p\u003e \u003c\/li\u003e \u003cli\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eLight Commercial Applications:\u003c\/strong\u003e Small office buildings, retail spaces, and multi-family housing hydronic systems.\u003c\/p\u003e \u003c\/li\u003e \u003c\/ul\u003e \u003cp class=\"ds-markdown-paragraph\"\u003eFor basic residential replacement needs, this pump offers superior performance to economy models, while for applications demanding maximum efficiency, consider Armstrong’s \u003cstrong\u003e[ECM High-Efficiency Circulator]\u003c\/strong\u003e 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 \u003cstrong\u003eHydraulic Institute’s website\u003c\/strong\u003e (External Link).\u003c\/p\u003e \u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003eContact our product specialists for assistance matching this pump to your specific application or to discuss your project requirements.\u003c\/strong\u003e\u003c\/p\u003e","brand":"TITANPARTHUB","offers":[{"title":"Default Title","offer_id":52160963903719,"sku":null,"price":2134.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0794\/7806\/3335\/files\/5b0b60dc-Pumps-ARMSTRONG-106284MF-136A-S-55-3-Cast-Iron-Pump.png?v=1780566419","url":"https:\/\/titanparthub.com\/products\/armstrong-106284mf-136a-s-55-3-pump-1-2-hp-cast-iron-circulator-hvac-hydronic-systems","provider":"TITANPARTHUB","version":"1.0","type":"link"}