Bradford White Defender Water Heater

How Does My Water Heater Work?

The lowly water heater in your basement or utility room may be one of the most-overlooked and hardest-working appliances in your home! When it stops working, it quickly becomes an emergency install to get hot water flowing in your home again. We probably miss hot water on tap as much as not having a refrigerator in the home!

So, how does your water heater work? We’ll focus on the most common unit, a tank water heater. The tank is a drum that holds heated water to be delivered to your bath and kitchen taps. The main working parts:Water Heater Diagram

  • Cold Water Inlet. Typically at the top of the tank is the cold water inlet, coming from your house main water pipe. You may have a Whole House Water Filtration System, or a Water Softener, located before your water heater’s cold water inlet. The inlet pipe is required by plumbing code to have a working shut-off valve close by.
  • Gas Burner or Electric Heating Element. At the bottom of the tank, there is a gas burner with a pilot light (or, in the case of an electric water heater, one or two electric heating elements inside the tank). Since the cold water comes in at the top of the tank, as the water heats, it naturally rises to the top.
  • Outflow Pipe. Outflow of heated water is also located at the top of the tank – and from there, supplying the rest of the house with hot water.
  • Thermostat. This mechanism tests the temperature of the tank’s water and activates the burner, which stays on until the water comes up to pre-set temperature. Most units are set to 120 – 140° F.
  • Anode Rod. In the middle of the tank is a metal rod, made of magnesium or aluminum, designed to sacrifice itself (instead of the metal in your tank and its components). The harder your inlet water is, the less time your anode rod will last – and then you’ll need a new heater! So it’s best to have filtration and/or a water softener in your water line before the heater, if needed. Jake the Plumber can test your water quality and make recommendations. If you suspect your water is hard, you will also see scaling or corrosion on your faucets, sinks, and tub.
  • Drain Valve. Close to the bottom of the tank is a drain valve, used to drain your heater for maintenance, moving the heater, or replacing it.
  • Temperature and Pressure (T&P) Relief Valve. This is a safety device that releases excess pressure in the tank for safety.
  • Venting. A gas water heater will also have venting and a flue to safely disperse fumes from the gas combustion. It will either be atmospheric-vented (attaching to your furnace’s venting out the chimney) or power-vented (an electric fan on the top of the water heater, forcing the combusted-gas air outside).

Bradford White Water HeaterIt’s a good thing to know how old your water heater is, what its capacity is, and other basic information about it. See our previous blog on Do I Need A New Water Heater? for signs to watch out for when your heater may be failing. You can find more information on our recommended unit, a Bradford White Water Heater.

-Deb Axness for Jake the Plumber