AMTROL was founded in 1946 on the premise that innovation, quality and service will be rewarded with customer loyalty and support. In 1954, we revolutionized the hydronic industry when we introduced EXTROL, the world's first pre-pressurized diaphragm expansion tank. This was followed in 1963 with the invention of the first pre-pressurized well tank and in 1967 with the invention of the refrigerant gas cylinder. AMTROL went on to invent the indirect fired water heater in 1980 and the thermal expansion tank in 1991. More recently the company introduced the first composite metal LP gas tank in 2005 and has since sold over 1 million of these tanks around the world. Throughout our history, AMTROL has been the world leader in the design and operation of the vital mechanical systems that are used to control hydronic heating and to store potable water.