Gas Water Heaters - Problems, Solutions, Repairs, Fixes, Maintenance and More!

illustration showing all of the parts of a gas water heater including the anode, thermostat, burners, dip tube and drain valve

Gas water heaters are the most common type of water heaters in residential settings. Gas gets the tank up to temperature about twice as fast as electrics do, and costs less than half what it takes for an electric water heater to produce the same amount of hot water.

Gas water heaters are less efficient than electric heaters, but electricity is much more expensive.

The tank should be firmly affixed to a structure such as the wall in earthquake prone areas to prevent a potential gas fire if the tank falls over and breaks the gas connection.

TPR Valve is a safety device for the water heater

Storage type units that have a tank have a TPR valve (and so do electrics). Some times tankless units have TPR valves, and sometimes they don't.

The TPR valve (Temperature Pressure Relief) also known as a T&P valve, pop-off valve,  or just relief valve, is a safety device on gas water heaters that releases pressure from the tank if the pressure or temperature reach unsafe levels.

The TPR valve is usually mounted on the top of the tank, but can sometimes be mounted on the side of the tank.

A manual release lever located on the relief valve. According to most manufacturers elief valves should be periodically tested by lifting the manual release lever at least once a year.

Due to the scalding potential of the discharge from the T&P valve, the outlet from the valve should be piped to a safe area. Typically they are piped down to within 6 inches of the floor or even outside of the dwelling at near ground level.  Check with your local building department for local building code requirements related to the relief valve discharge plumbing.

Anode Rod

The sacrificial anode is a metal rod usually magnesium or aluminum which helps prevent corrosion of the metal tank. Electrolysis eats away the metal anode instead of the metal of the tank. Once the anode is gone the tank itself begins to corrode. To prolong the life of the tank, make sure your anode rod is still there, and replace it when needed.

The anode is screwed into the top of the tank and can be replaced.  Sometimes the anode is built into a special outlet fitting. Softeners can cause the anode to wear out more quickly.

Bacteria can react with magnesium anodes causing hydrogen sulfide which can cause a rotten egg odor. Switching to an aluminum anode rod can help eliminate the odor problems.

Water Heater Dip Tube

The dip tube is a long narrow tube that directs incoming cold liquid to the bottom of the water heater tank, preventing pre-mature mixing of incoming cold liquid with the out going hot liquid at the top of the tank.  Without the dip tube, or with a broken dip tube,  it may seem as though you run out very quickly, or you just get a luke warm temperature. More about dip tubes

Thermostat

The thermostat senses when the tank drops below a certain pre-set temperature and causes the burner to come on.  When the desired temperature is reached, the thermostat shuts off the burner. There is a knob that allows you to set the temperature to warm med or hot.

Drain Valve

The drain valve allows the tank to be drained for various reasons including periodic removal of sediment or for replacement. In areas with high mineral content, it is recommended to drain at least 5 gallons from the drain valve every six months or so to prevent sediment build up.

Avoid cheap plastic drain valves that can easily break off.  Replace plastic drain valves with a good metal ball valve.  Ball valves make it easier to drain the water heater tank as well.