WATER HEATERS 101
Understanding how your Houston water heater works

It’s in your best interest to understand how your water heater in Houston works so that you can properly maintain it and get the most out of your home’s hot water system. If your water heater stops working as it should, knowing the basics can potentially save you time and money, and will better prepare you for repair or replacement options. Although there are various water heater types, the two most common are tank water heaters and tankless water heaters. Both tank-type and tankless models can be either gas-fired or electric. The majority of Houston homes use tank water heaters. However, tankless water heaters are becoming standard in new developments, so if you live in a newer home or a home that has recently been remodeled, you may have a tankless system supplying hot water to your home.

TANK WATER HEATERS
Tank water heaters are easy to spot; they comprise a large cylindrical hot water storage tank standing on end with pipes coming out of the top and a drain cock towards the bottom. Tank-type water heaters not only heat water but also store it in a tank until it’s ready for use. Typically, Houston water heater tanks are made of steel and lined with glass to prevent the steel from rusting. They are also insulated to keep the water hot between heating cycles.

How Hot Water Storage Tanks are Sized
Houston water heater tanks range in size, with the smallest tanks holding around 23 gallons and the largest holding more than 56 gallons. For the purpose of cost and efficiency, it’s important to have an appropriately sized hot water storage tank. If it’s too big, you may be spending more money than necessary to heat up the water within the tank. If it’s too small, your family may run out of hot water throughout the day.

The size of your home, appliances, and family are all important factors to consider when determining the size of your hot water storage tank. But the most important question to ask yourself is, “How much hot water does my family use?”. If you only have four people living in your home, but they all take hot baths (which consume more hot water than showers) and frequently wash their clothes, you may need a larger sized storage tank. Likewise, if you have a large family, but everyone takes showers and conserves water, then a medium sized hot water storage tank may suffice.

How Tank-Type Houston Water Heaters Work
The two pipes coming out of the top of every water heater tank are the supply and delivery pipes; one is the cold-water inlet pipe and the other is the hot-water outlet pipe. The cold-water inlet pipe carries cold water from your home’s water supply into the tank where it comes out of the dip tube, filling the tank with water to be heated. The hot-water outlet pipe carries hot water from the tank to the various appliances and faucets around your home when they need hot water.

All hot water storage tanks include a critical safety feature: the temperature and pressure valve, which is often referred to as the T&P valve. If the water gets too hot or the pressure in the tank is too high, the T&P valve will open and deposit water through a pipe running outside of the tank that usually ends 6 inches above the ground. We advise homeowners to keep a bucket underneath the T&P deposit pipe to catch water in case the T&P valve opens. The T&P deposit pipe should not be connected to a drain; if the valve opens and the water goes down a drain, you might miss early warning signs of a problem in your water heater that could worsen if not addressed.

Another feature found in Houston water heater tanks is a magnesium rod known as a sacrificial anode rod. Corrosion and rust are primary reasons that most tank-type water heaters fail. Sacrificial anode rods are designed to corrode, temporarily saving the steel casing and internal components from rusting (hence why this rod is referred to as ‘sacrificial’). Because the anode rod wears away over time, it’s important to inspect and replace it as needed in order to maintain your water heater. If the sacrificial anode rod is not replaced once it has been fully corroded, your hot water storage tank will begin to corrode, meaning you will probably have to replace it prematurely.

In addition to checking the sacrificial anode rod at least once a year, it’s also important to flush your hot water storage tank to prevent build up of minerals and deposits that slow down the heating process, accelerate corrosion, and destroy internal components. (If your water heater sounds like a jackhammer, it’s because calcium and magnesium in your water have formed into solid rocks inside of your water heater). The drain cock located at the bottom of the hot water storage tank is where you or a service technician can flush the tank.

Important: Before flushing your hot water storage tank, you must first shut off the thermostat, turn off the gas, close the cold water valve, turn on a hot water valve in a sink or tub in your home, and open the T&P valve. It is also highly recommended that you connect a garden hose to your drain cock to direct the water being flushed outside of your home. To take advantage of our water heater flush and inspection service, contact us today!

That covers the basic operations, safety and maintenance features of tank-type water heaters. But now you may be asking yourself, “How does the water get hot?” That depends on whether you have a gas-fired tank-type water heater or an electrical tank-type water heater.

How Gas-fired Tank-type Water Heaters Heat Water
Gas-fired tank-type water heaters use a burner centered underneath the tank to heat the hot water storage tank, which in turn heats the water within the tank. Gas is fed to the burner through a gas control valve and thermostat switch that are usually located toward the bottom of the hot water storage tank. The gas coming out of the burner is ignited via pilot light. Natural gas and liquid propane (LP) are the two most common types of gases used in gas-fired water heaters.

The combustion of gases within gas-fired tank-type water heaters create by-products such as carbon dioxide, carbon monoxide, and nitrogen oxide that are removed through a flue baffle that runs through the water heater storage tank. The flue baffle turns into a vent that exits through the top of the hot water storage tank and runs through a wall or ceiling, releasing the by-products outside of the home.

Wrapped around the vent that comes out of the top of a gas-fired hot water storage tank, there should be a round, bell-shaped (or cone-shaped) piece of metal called a draft hood. This hood prevents backdraft, which is when the combustion by-products are blown back into the home or water heater system. Not only does backdraft prevent the venting of harmful by-products but it can also blow out the pilot light

How Electric Tank-Type Water Heaters Heat Water
Electric tank-type heaters utilize electrical-resistance heating elements located within the hot water storage tank to heat up the water within the tank. There are usually two heating elements inside the storage tank, one located near the bottom and one located in the middle of the tank. A thermostat that controls and senses the temperature of the water within the tank delivers power to the heating elements when it detects that the temperature of the water is below the temperature set on the thermostat. Instead of a vent, electric tank-type water heaters have a 220-volt power supply cable going into the top of the hot water storage tank that supplies electricity to the thermostat and heating elements.

TANKLESS WATER HEATERS
Electric tank-type heaters utilize electrical-resistance heating elements located within the hot water storage tank to heat up the water within the tank. There are usually two heating elements inside the storage tank, one located near the bottom and one located in the middle of the tank. A thermostat that controls and senses the temperature of the water within the tank delivers power to the heating elements when it detects that the temperature of the water is below the temperature set on the thermostat. Instead of a vent, electric tank-type water heaters have a 220-volt power supply cable going into the top of the hot water storage tank that supplies electricity to the thermostat and heating elements.

How Gas-Fired Tankless Water Heaters Work
TanklessAs mentioned above, gas-fired tankless water heaters only heat up water when you need it. How does this work? When you turn on a hot water valve or an appliance that draws hot water such as a washing machine or dishwasher, the gas-fired tankless water heater will draw cold water in through the cold-water inlet pipe on one side. The cold water flowing into the system hits a flow sensor inside the unit that relays a signal to the computer within the water heater. The computer pulls in gas and ignites a fire within the contained burner, which provides heat to the heat exchanger. The incoming water is then circulated through the activated heat exchanger, heating the water to the temperature set on the thermostat before leaving the system through the hot water outlet pipe where it is directed to the appropriate faucet or appliance. This all happens within seconds, effectively giving homeowners instant access to hot water. When there is no demand for hot water, the system shuts itself off.

Similar to gas-fired tank-type systems, gas-fired tankless systems include a vent that removes any by-products created during the combustion process. A small fan underneath the burner propels the by-products up through the vent, where they are carried outside of the home.

Point-of-Use Tankless Water Heaters
Point-of-use units are used to quickly supply hot water to a source not located near the home’s central water heater. These units are not intended to replace a water heater, but instead are luxury add-ons to a home with a functioning water heater. Much like whole-home tankless water heaters, point-of-use units don’t have to keep a tank of water warm and only operate when hot water is in use.

Circulation Pumps
Point-of-use units are used to quickly supply hot water to a source not located near the home’s central water heater. These units are not intended to replace a water heater, but instead are luxury add-ons to a home with a functioning water heater. Much like whole-home tankless water heaters, point-of-use units don’t have to keep a tank of water warm and only operate when hot water is in use.

• Diagnosing the problem: $49 waived with repair
• Price: Starting at $200
• Average time to complete: 3 hours