Buying Guide: AMTROL Expansion Tanks Posted on January 2, 2025 You may not see it, but expansion tanks are a vital component of plumbing and heating systems. Every time you use hot water, these tanks absorb the excess water pressure caused by thermal expansion. And when it comes to expansion tanks, AMTROL is one of the eminent names. Read on to learn more about this renowned brand, and what sets their expansion tanks apart from the competition. The History of AMTROL AMTROL got its start in 1946 from industry pioneer Henry Fleischer. Working out of West Warwick in Rhode Island, Fleischer established the American Tube Products, focusing on plumbing and water tank systems. A few years later, the nascent company is credited with inventing the first diaphragm expansion tank in 1954, which revolutionized the plumbing and HVAC industries. Over the intervening years, the innovative upstart introduced a string of industry-first milestones that made it a byword for innovation in the market: 1963: the first pre-pressurized tank 1967: the refrigerant gas cylinder 1980: indirect-fired Hot Water Maker 1986: top coil indirect Hot Water Maker 1991: the thermal expansion tank Since then, AMTROL has grown into a globally recognized leader in water system solutions, offering innovative products for residential, commercial, and industrial applications. Their reputation is built on a foundation of quality, reliability, and technological advancement that made it a name in the industry. What Sets AMTROL Expansion Tanks Apart 1. Innovative Design As the inventor of the thermal expansion tank, AMTROL paved the way for the rest of the industry. The company’s diaphragm and pre-pressurized tanks set the standard for durability and performance. Their unique designs help prevent air and water absorption, ensuring long-lasting operation. 2. Advanced Materials AMTROL uses high-quality steel and butyl diaphragms for maximum durability and resistance to corrosion. Their tanks are engineered to withstand varying pressures and temperatures. 3. Comprehensive Testing Each AMTROL tank undergoes rigorous testing to meet industry standards for safety and performance. The brand boasts ISO 9001 certification which it obtained as early as 1992. 4. Wide Compatibility AMTROL tanks are designed to work seamlessly with a variety of plumbing and heating systems, including hydronic heating, potable water, and well water systems. 5. Proudly Made in the USA AMTROL takes pride in manufacturing its products in the United States, adhering to strict quality control measures. All tanks continue to be manufactured in the company’s Rhode Island facility since 1972. 6. Professional certification AMTROL products are industry-certified to meet stringent quality standards, including: ASSE – Shock Suppressors ASME Certificate– The American Society of Mechanical Engineers CE Mark – European Pressure Equipment Directive (PED) DOT – Well Tanks and Thermal Expansion Tanks Factory Mutual (FM) Approval – Fire-X-Trol and Surge-Trol IAPMO – CA and VT Lead Plumbing Law, Potable Water Products ISO Certificate– Quality Management Certification National Board Certificate– ASME code vessels NSF Std 58 – Reverse Osmosis Tanks NSF Std 61 – Well Tanks and Thermal Expansion Tanks NSF Std 61 – Bladders, ASME Well and Thermal Expansion Tankss OSHA– Occupational Safety and Health Administration – SDS sheets State of MA – Hot Water Makers, Well Tanks, Thermal Expansion Tanks and Pressurisers Transport Canada – Cylinders, Well Tanks and Thermal Expansion Tanks UL – Electronic Controls, Fire-X-Trol and Surge-Trol Water Systems Council – Well Tanks This makes the AMTROL tanks worthy of its slogan “Well above the rest”. AMTROL Expansion Tank Lineup As one of the industry pioneers and leaders, AMTROL offers a diverse range of expansion tanks tailored to various applications: 1. Therm-X-Trol® Series These are the residential tanks designed for domestic hot water systems to control pressure caused by thermal expansion. Models include both in-line and floor-standing options, with capacities ranging from 2 to 86 gallons. The tanks feature the company’s patented CAD-2 diaphragm design ensures consistent performance and longevity. Other features include the brand’s patented Turbulator®, patent-pending antimicrobial liner, and patented InSight® service indicator cap. AMTROL’s tanks also boast the highest precharge at 50 PSIG as well as the thickest diaphragm, made of heavy-duty butyl. Featured Therm-X-Trol tank: Amtrol ST-5 Therm-X-Trol In-Line Thermal Expansion Tank for 40 – 50 Gallon Water Heaters The ST-5 has a tank volume of 2 gallons and is 8″ in diameter by 13″ high. It is constructed of stainless steel with stainless steel connections. It offers a maximum working pressure of 150 PSI with a factory pre-charge of 50 PSI and a maximum operating temperature of 200°F. It includes a Fresh Water Turbulator – a patented diffuser that agitates the incoming water to keep it fresh and clean while its water-jet scrubbing action prevents sediment for collecting inside the tank. Amtrol Thermal Expansion Tanks also have an InSight Indicator Cap with a patented sight glass that changes color when your expansion tank needs to be replaced! Price: $67.00 Amtrol ST-5 Therm-X-Trol In-Line Thermal Expansion Tank for 40 - 50 Gallon Water Heaters A Thermal Expansion Tank is a requirement, by law, when your hot water heater includes a back flow preventer at your water main or a check valve anywhere in you... View Product Featured Therm-X-Trol tank for POU systems: Amtrol ST-1 Therm-X-Trol In-Line Thermal Expansion Tank for Point Of Use and Tankless Water Heaters The ST-1 is designed specifically for use with either point of use or tankless water heaters with up to 2 gallons of water volume. It measures about 3.4″ x 4″ and is constructed of stainless steel with stainless steel connections. It offers a maximum working pressure of 150 PSI and a maximum operating temperature set point of 140°F. The Butyl diaphragm inside the steel tank keeps your potable water from contact with the steel and is sent back into the system when the call for hot water comes again. It comes with a 7-year limited warranty. Price: $31.00 Amtrol ST-1 Therm-X-Trol In-Line Thermal Expansion Tank for Point Of Use and Tankless Water Heaters A Thermal Expansion Tank is a requirement, by law, when your hot water heater includes a back flow preventer at your water main or a check valve anywhere in you... View Product 2. Extrol® Series This line is specifically for hydronic (hot water) heating systems. It uses pre-charged, diaphragm-style technology to reduce air infiltration. The series is available in a variety of sizes to accommodate both residential and commercial systems from 6.4 gallons (24 liters) to 3,963 gallons (15,000 liters). These robust tanks boast a maximum working pressures up to 300 PSIG (21 bar), made possible through the industry’s thickest diaphragm as well as thickest replaceable bladder. Featured Extrol Series tank: Amtrol EX-30 Extrol 4.4 Gallon In-Line Hydronic Heating Expansion Tank The EX Series is specifically for use in non-potable, closed, hydronic heating and chilled water systems. Depending on your type of system, the EX-30 is designed to work with BTU outputs of 50,000 – 150,000 heating systems. It has a tank volume of 4.4 gallons. This tank uses the company’s patented InSight Indicator Cap, which changes color when your expansion tank needs to be replaced. The sight glass remains clear/white under normal operation, but when it becomes discolored, it is time to replace your tank. Price: $62.00 Amtrol EX-30 Extrol 4.4 Gallon In-Line Hydronic Heating Expansion Tank Amtrol ExTrol Expansion Tanks for residential hydronic heating systems take on the expanded fluid in closed-loop systems. The purpose of an expansion tank is ... View Product 3. Well-X-Trol® Series This series is for well water systems to maintain consistent pressure and reduce pump cycling. It includes models for standard residential wells as well as high-capacity commercial systems. The tanks are considered the standard of the industry, boasting high-strength steel capable of 150 PSIG working pressure; patented Turbulator® water circulator device; and patent-pending antimicrobial liner that kills bacteria on contact. 4. Chill-X-Trol® Series As the name suggests, this line is for chilled water and cooling applications in HVAC systems. It prevents air binding and maintains system pressure. The tanks are constructed from non-corrosive materials to withstand cooling system conditions. 5. Specialty Tanks AMTROL also manufactures expansion tanks for niche applications, such as solar heating systems and industrial processes. Customizable options are available for specific system requirements. Choose Your AMTROL Tank Today AMTROL’s expansion tanks not only pioneered the industry, they continue to set the standard. With a legacy spanning over seven decades, AMTROL continues to lead the market with relentless innovation and unmatched quality and material construction. Whether you need a solution for domestic hot water, hydronic heating, or well water systems, check out our AMTROL lineup and enjoy the brand’s exceptional reputation backed by our fantastic customer service. Mickey Luongo Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.
