The Gas Hot Water Heater

Your gas hot water heater is a simple device which will normally give you many years of trouble free service, but the presence of gas in your home leads to several precautions which must be taken. The first and best way to insure that your heater is functioning in a safe and proper manner is to call one of our Gas Fitters to inspect your tank and make minor repairs or suggest replacement when necessary, but for those of you with an inquiring mind who want to know more about gas hot water heaters we have provided the following information.The standard “tank type” water heater found in most homes will normally provide years of trouble free operation, but it will need a bit of maintenance every now and then.  Unlike tankless water heaters the tank type water heater heats cold water and stores the hot water until it is needed. This brief explanation will serve as a guide to understanding your gas hot water heater.Cold water is supplied to the tank and injected at the bottom of the tank through a dip tube. The denser cold water stays there and is heated by the gas burner. As the water heats up, it naturally rises  and is drawn off by the hot water discharge pipe as it is needed. Notice in the drawing below that the hot water pipe is much shorter than the cold water pipe. This is so that that only the hottest water is being used from the tank. The gas hot water also has several safety features, which are explained later.Let’s take a look at each major component of the hot water tank.

Cold Water SupplyCold water is provided to the tank by a cold water supply line and controlled by a shutoff valve. It is important to know where the water supply shut off valve is located so maintenance can be performed on the tank.Hot Water DischargeThis is the business end of the hot water heater and the hot water line is what supplies all your sinks, tubs, showers and appliance needing hot water.Construction of the Hot Water TankThe tank jacket may be made of either steel or plastic and surrounds the insulation and the pressurised steel storage tank. Between the storage tank where the hot water is stored and the tank jacket there normally is fiberglass insulation to reduce the heat loss from the heater. In colder climates it may be a good idea to  add extra insulation to your heater by adding a fiberglass insulation tank jacket to the outside of the hot water heater. if you could see inside the heater you would see a metal tube called the dip tube, which is where the cold unheated water comes into the tank. Since the cold water is denser than hot water, the cold water settles at the bottom of the tank where it is heated by the gas burner. Thus there is a continual circulation of the water inside the tank which insures that all the water inside the tank is about the same temperature.In almost all glass-lined tanks there will also be a magnesium or aluminum rod in the tank, known as a sacrificial anode. This anode works by preferentially corroding itself instead of purpose instead of allowing the metal tank to corrode. In some cases there may not be a separate anode but will use the hot water outlet as and anode.”