If your hot water system relies on a storage tank for ready access to hot water, you may find that you have excess pressure building up in the tank due to the expansion of the water when it is heated. This added pressure can cause damage to both the hot water tank and your plumbing. If you are using a tank-based hot water system, you should add an expansion tank to provide somewhere for the water to go. Here's a look at the installation basics to add an expansion tank to your hot water system.
When to Install the Tank
The easiest time to install an expansion tank is when you're installing the hot water system. That gives you the freedom to customize the placement of each of the components according to what you have room for. However, that doesn't mean you can't install one in an existing system. In either case, you'll want to invest in some galvanized pipes to connect the two tanks. Galvanized pipe is a good choice, because it's affordable and durable.
How to Install the Tank
Locate the small section of pipe sticking up from the top of the tank. This small piece of pipe is referred to as a nipple. Apply a small amount of pipe joint compound on the nipple, then wrap a single layer of plumber's tape on it as well. Attach a galvanized tee to the nipple where you wrapped the plumber's tape. If you've never worked with pipe tees, you'll recognize them by the "T" shape to the pipe.
Tighten the pipe tee so that it's hand-tight and the ends are facing in the direction where you're running the pipes. If you can't get the tee pointed in the right direction, you may have to turn your hot water tank a bit. To get the tee completely tight, you may need to use a pair of pliers on the fitting of the tank and a pair of pliers on the tee to turn it with a bit more leverage.
Use this same process to attach an elbow pipe to the longer pipe nipple that's protruding from the top of the tank. Apply a bit of joint compound and plumber's tape on the pipe that's attached to the expansion tank, then screw the elbow pipe to the expansion tank pipe.
Once the expansion tank is attached to the water heater and your water lines are in place, you can turn on the water supply to the tank and allow it to fill. Check your fixtures for leaks, and use plumber's tape if necessary to seal threads. If you aren't comfortable doing the installation on your own, a local plumber like Salinas & Sons Rooter Service can help you get everything connected properly.