An expansion tank is a required component for all hot water boiler systems, and is designed to control system pressure and help reduce energy consumption of heating and circulating operations. These Amtrol expansion tanks are factory pre-charged and 100% tested to keep the diaphragm flush against the tank when the system is first filled with cold water. As the system water temperature increases, the expanded water is absorbed by the tank. As the system water temperature reaches its maximum, the diaphragm flexes against the air cushion to allow for the increased water expansion. These expansion tanks feature a Butyl/EPDM diaphragm for superior air retention, nine times better than natural rubber. 

The AMTROL FILL-TROL® system consists of a specially adapted EXTROL pre-pressurized, diaphragm-type expansion tank, and the FILL-TROL, a specially designed, automatic, pressure-reducing fill valve.

Standard Features

• Pre-pressurized, diaphragm-type expansion tank with a standard charge of 12 PSI
• Tanks are of welded-steel construction Extrol® Tanks
• Hydronic heating systems and can be used in glycol systems
• Recommend installing Extrol® into bottom of purger using a single 1/2" nipple for both pipe connection and mounting
• Can be used in hot water heaters, hydronic heating systems and in glycol systems
• Includes Fill-Trol®, automatic pressure reducing valve
• Fully adjustable up to 100 PSIG maximum working pressure Therm-X-Trol® Tanks
• Designed to accept increased water volume created when storage tank is heated, keeping system pressure below relief valve setting
• System connection 3/4" brass
• Listed by IAPMO, SBCCI and NSF61