Product Overview
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 your plumbing system. If you have installed a circulation pump anywhere in your house, you have a check valve. Additionally, backflow preventers have become a more prominent addition to codes in various areas. Whenever water is heated, it expands. In the past, excess or expanded water would flow back into the public water system, however backflow preventers stop this from happening, creating a need for a place for that expanded water to go. For example if you have a 40 gallon hot water heater there could be an additional 1/2 gallon of water created even without any demand.
Typically, as a homeowner, your hot water heater is not something you look at or check on a regular basis. You install it (or have it installed) and forget about it until one day you have a problem! You may or may not notice a little water coming from your water heater. It could come from the temperature pressure relief valve in the form of just a few drips or a gush of water. The cause for leakage could be linked back to the expansion of the water in the tank and now it has nowhere to go. When hot water is heated, it expands. That expanded water needs somewhere to go. The purpose of a Thermal Expansion Tank is to act as an overflow for the excess water created by the water heating, maintaining safe expansion pressure. 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.
A Thermal Expansion Tank, such as the Therm-X-Trol ST-1, can be added to your tankless or point of use water tank at any time, but if you are installing a new water heater a thermal expansion tank should be added! It will protect your water heater against thermal expansion.
A Thermal Expansion Tank is a small metal tank - usually between 2.1 to 4.5 gallons. The ST-1, however, is designed specifically for use with either point of use or tankless water heaters with up to 2 gallons of water volume. It is smaller, about 3.4" x 4" and constructed of stainless steel with stainless steel connections. The ST-1 offers a maximum working pressure of 150 PSI and a maximum operating temperature set point of 140°F.
The thermal expansion tank is typically installed on the cold water line between the water heater and the backflow preventer.
Tech Specs
California residents see Prop 65 WARNINGS
WARNING!
Warning: Cancer and Reproductive Harm - www.p65warnings.ca.gov
