Water Heater - After tank failed    Basic Gas Water Heater

All Around Plumbing Frisco – Plano – McKinney

Basic Components of a Gas Water Heater


At All Around Plumbing & Leak Detection Frisco TX we want to be your plumber in Frisco.  We wrote this to help our customers in Frisco, Plano, McKinney and the Allen TX area.  The type of water heater we will be discussing is a tank type water heater. The tank is made of steel then vitreous glass is bonded to the inside of the tank of your water heater to keep it from corroding. The process can have its limitations. Even a small amount of metal exposed or not coated will start to rust. The difference between manufactures can be significant. In other words you get what you pay for.

How your water heater slows down the corrosion process is built into the design. The steel tank even though it has a glass lining can’t rust right? Wrong the lining can have imperfections or cracks. There are always some things that fails in the tanks lining other wise they would never fail. Your water heater has another way to fight the corrosion an anode rod. This sacrificial anode rod is made up of a steel wire coated in aluminum or magnesium. Over time the anode rod does just what it was designed to do corrodes. This way the anode sacrifices itself and the tank stays intact without corroding. In this way any part of exposed steel is protected, Your water heater design is a true modern marvel. Just think of life without one.

The next part of your water heater are the dielectric nipples located at the top of your water heater they are there for the same reason to stop corrosion from the joining of two different metals. When you have a steel tank the dielectric nipples are plastic coated and are there to stop electrolysis. This is a small current generated when you join to dissimilar metals. The dielectric nipple stops this process and gives you a place to connect your incoming water supply. Don’t let your water heater fail and flood your home.

Just located below the dielectric nipple on the cold side of you water heater you have a dip-tube. This is a plastic tube that carries water to the bottom of the tank where it can be heated and not mix with the hot water at the upper end of the tank. Hot water rises just like hot air. Just like air cold water is denser and heavier, so it stays at the bottom of the tank until heated and rises. If your dip tube breaks water in your heater could be just warm and you will find yourself running out of hot water faster. Did you know over 20 million gas and electric water heaters built between 1993 and 1996 about 90 percent of all hot water heaters built during this period contain defective polypropylene dip tubes. Does your water heater look rusty and old it might be time to call the Frisco Plumbers at All Around Plumbing.

The T & P valve located in the top or side of your water heater is there for your safety. If it is installed incorrectly your water heater is a bomb. In the State of Texas 500 hot water heaters explode each year. Water Heater Statistics come from TSBPE in Austin. For this reason the state requires an inspection on all water heater installations. The T in T & P Valve stands for temperature. If the temperature climbs in excess of the manufactures specifications this valve opens up and relieves the pressure before the tank ruptures on your water heater. The P stands for pressure, so you have a temperature and pressure relief valve. It is the most important safety devise on you hot water heater. Is your water heater safe and do you know.

The thermostat or temperature control regulates the amount of heat delivered the water heater. If this fails your only protection is the T & P valve. On a gas water heater you have a vacation setting for times you might be out of town and don’t want to waste energy. You can also turn your water heater to vacation when you are doing repairs to your domestic water system and have the water off. The important thing to remember is not to turn your water heater up to high. Set your water heater at 120 degrees but before anyone uses the hot water always test to see if it is to hot. Thermostats can malfunction or be mislabeled so always check after adjusting. It only takes a few seconds to burn a small child and a lifetime to heal.

The next part of your water heater is the burner assembly. This is where you start to heat the water. The burner assembly is where you have your pilot and gas burner itself. It is important to make sure the burner is adjusted properly and you have a nice blue flame. This is to prevent carbon monoxide poisoning. Yes your water heater can poison you to. The burner assembly is connected to the flue which goes all the way to the top of the water heater. Trouble lighting your water heater call the Frisco Plumbers at All Around Plumbing & Leak Detection.

Where the flue exits on top of the heater is where you place your vent. Correct sizing is very important here. Be sure and know your manufactures specifications on proper venting and sizing. The next things to consider is the proper venting material and insure there are no leaks in the vent piping. Other things to consider are if the vent pipe passes through any combustible material or sheetrock. If so you must keep a one inch clearance all the way around the vent pipe and the vent piping must be double walled at this point for the rest of the run. One more thing the vent piping must also be properly secured.

Your burner assembly is connected to the gas supply with a flexible gas connector or flex line. Your flex line can not pass through a wall or cabinet only an open area. You can not conceal it in a wall. The gas supply should always have a service valve located within 3 ft of your water heater within the same room. This valve should be a ball valve type that can be turned off without any tools (red handle valve.) The flex line should always be replaced each time you replace the water heater.

The water tank is covered with an insulation material as per energy code to keep the water in the tank hot and to prevent heat loss. The final outer covering is the shell. When you look at the shell you are not seeing the tank so it can be hard to judge the condition of the tank from looking at the shell sometimes. If the shell looks like hell the tank is usually in bad shape to.

Down near the bottom of the tank there is a drain for the tank. This is there to drain sediment out of the water heater and to service the unit. This drain is usually inadequate and does a poor job of draining the tank. The opening is to small and made very cheaply. A better heater usually has a better drain you get what you pay for. Do you know how to drain your water heater?

The last thing is the dielectric fitting on the hot side of the tank where hot water exits the water heater. This is where you make your connection to the hot side of the domestic system.

This covers some of the basic things about a gas water heater there is a lot more to a water heater and installation than this small article. If you have questions please consult a licensed plumber in your state. Each State has its own codes and laws. The following information is for that purpose only. If you don’t know what you are doing with a water heater call us we can help you.


A. O. Smith (Hot Water Heaters)

American Water Heater

Bradfordwhite.com (water heaters)
Spec sheet for gas heaters


Rheem/Ruud (water heaters)
Spec sheet for Gas water heaters

State Industries, Inc. (water heaters)

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