Things expand when they heat up; water is no exception. So if you have a conventional water heater, you’d better have somewhere for that water to go! In some older homes, the plumbing system is “open,” meaning any water from the water heater can backflow into the water main and out of your home. Increasingly, however, plumbing systems are becoming closed off as backflow preventers are installed to protect plumbing systems from inlet water pressure, which is increasing in many areas as population increases.
Closed Plumbing Systems
A closed plumbing system is a plumbing system that does not have a way for water to flow backwards toward the meter or city supply. Put simply, if your home has a backflow preventer then you are on a closed plumbing system.
If your plumbing system is “closed,” the water in your water heater will have nowhere to go as it expands. And since water is incompressible, the increased volume will sharply increase the pressure in your unit, potentially causing damage to it or other appliances.
Water Heater Expansion Tanks
A thermal expansion tank is a pressurized tank that sits on your cold water line at or near the water heater. The tank contains a pressurized bladder that expands as water presses against it, giving that water a place to go and reducing the pressure on the rest of your water heater as the volume increases.
Thermal expansion tanks are recommended by all water heater manufacturers and are required by almost all states’ plumbing codes. Each manufacturer has different recommendations as to the exact location and orientation of the expansion tank.
Before you install a water heater expansion tank, you should find outthe size of your water heater and the water pressure at your home. This is important is the more water your water heater holds, the greater the volume your expansion tank has to handle. For example, 40 gallons of water heating from 50 F to 120 F will add about 1/2gallon of water from thermal expansion. You need to match the water pressure so the air bladder functions properly in your expansion tank. If the pressure coming in is greater than what your tank is rated for, it will fill up and do nothing but fail prematurely.
If you need to install a water heater expansion tank, or if you need any other water heater services in Maryland, Virginia or Washington, DC, call Magnolia Plumbing!