When water is heated it expands. If your system is “open” then water can back-flow into the water main and this extra expanded water simply flows out of your home back out your cold pipe.
More and more, home plumbing systems are being closed off and back-flow prevention valves are being placed between homes and the water main. This is done for a variety of reasons.
For example, valves are placed between homes and water mains to protect plumbing systems from inlet water pressure. Water pressure is increasing in many cases in order to meet the demands of more densely populated areas.
If your system is “closed”, then this means when you heat your water and it expands, this increased volume has nowhere to go. This causes sudden increases in water pressure which can damage your water heater, fixtures and other appliances.
A thermal expansion tank is a pressurized tank that sits on your cold line – typically near or on your water heater. The tank contains a pressurized bladder. As water expands, it pushes against this bladder giving the increased volume a place to go, preventing rapid pressure increases due to thermal expansion.
Expansion tanks are currently recommended by all major water heater manufacturers. In fact, expansion tanks are required by state code if your system is closed in most of the states where we work. Local enforcement of this code varies from city to city.
Our technician will test your system to determine if it is open or closed. If your system is closed, installing an expansion tank may lengthen – and in some cases double – the life of your water heater by preventing wear and tear. In addition, if your home has a history of leaky faucets or other appliances that wear out prematurely, an expansion tank may fix your problem. Learn More.