Modern residential water heaters may be the longest lasting, safest and most maintenance free appliance in our homes. That does not mean they never fail and can’t be dangerous and never need any maintenance. Here are some things to be aware of and check on occasionally.
Today we have traditional storage tank type water heaters that have been around for years and the newer tankless water heaters. Both gas use either gas or electricity to heat water. In this article we are not going to get into which type is better. That is a different subject with its own can of worms.
Both types share some common safety issues, and each have some maintenance needs. Either can leak water. The storage tank type may have more places to leak but even the tankless can leak water. For this reason, it is common to put a pan under each kind with a drain line to the exterior. This is especially true if your water heater is in the attic (as many are) or any area of your house where a water leak could cause damage.
Another thing to understand is the temperature & pressure relief (T&PR) valve. All water heaters have one as a safety device. Its function is to discharge excess pressure should the water heater malfunction. It is a “pop off” valve that is designed to open if the water temperature hits or exceeds 210 degrees Fahrenheit or if the water pressure hits or exceeds 150 PSI.
The T & PR valve is located on the top or on the side near the top of storage tank units and underneath, the tankless water heater in the hot water line. These should have discharge or drainpipes which terminate either outside or to some appropriate (designated by your local code authority) location. This may be a floor drain or sump. When looking at this termination Imagine what would happen if the valve suddenly opened and very hot water at 150 PSI was discharged. Would that cause any damage?
As far as maintenance goes, there is not much to do in either case bit it is still important. With a drain pan, just monitor its condition. Make sure it is free and clear of any debris that might block the drain and be sure it is not rusting. Rust can eat a hole in the pan and render it useless. Also check that it was not bent or damaged during installation.
The T & PR valve has a silver lever hanging from it. If you lift this lever, it will discharge water to the drain termination. Be sure you are comfortable with the termination point first. The water heater does not need to be operating to do this if it has normal water pressure it will allow a discharge. It will also flush out any corrosion that may be building up inside the unit that is not visible.
If the lever is difficult to open or will not open, call a plumber to replace it immediately. If it leaks after you test it, you should also call a plumber and have it replaced. Manufacturers of T & PR valves recommend testing them at least once a year.
Storage type water heater manufacturers recommend flushing them annually. Almost no one does this, but it will make your unit last longer and remain more efficient. To do this, first turn off the water heater! With gas units there is an off position on the control valve and usually a gas shut off valve very nearby. With electric units there should be an electric disconnect near the unit or in older installations you may have to find the breaker and turn it off.
Then, attach a garden hose to the tank drain. Make sure the garden hose discharges to a safe location, either outside or in a bathtub. Now turn off the cold water coming into the unit, open a hot water line somewhere in the house close to the unit and open the tank drain valve.
After the tank is empty just close the drain valve, remove the garden hose, and open the cold-water inlet valve. Leave the hot water valve open while filling to allow air to escape the system. When water starts to flow at the hot water valve just turn it off. Now it is safe to relight the gas unit or turn the electric unit back on.
Tankless water heaters benefit greatly from annual cleaning or de-scaling. This is a bit more difficult but worth the effort. Rather than writing several paragraphs here explaining how to do it we will direct you to a YouTube by Matt Risinger from Austin, TX.
If you are buying a home, you should get it inspected by a Best Texas Home Inspector.