A neighbor had to replace a malfunctioning hot-water heater just two days before a nearby relative was forced to do the same thing.

Obviously, it was a coincidence, but it made everyone who heard about it check out their own hot-water heaters, to see if the ghost was about to be given up there as well.

Thus, I thought it might be wise to write a bit here about traditional tank hot-water heaters, since they have been known to break without warning.

The following advice is from what manufacturer A.O. Smith calls its "university." My plumbers, past and present, have installed only A.O. Smith or Bradford White heaters in my houses, so what they say goes:

Check water pressure at the drain valve or the hose bib. If it's above 80 pounds per square inch, install a pressure-reducing valve. (Call a plumber for this.)

To protect appliances, most experts recommend setting the pressure-reducing valve at 50 to 60 psi.

Check for an expansion tank, which is required by plumbing codes for closed plumbing systems. Operating a water heater on a closed system without an expansion tank will damage the heater and other appliances.

Pressurize the expansion tank with air before installing on a cold-water line. The air pressure should match the water pressure.

Inspect valves - temperature and pressure-relief valves - per instructions on the label. Valves will drip if the water pressure is too high, or due to thermal expansion on a closed plumbing system.

Drain and flush. Turn off the cold-water supply and open the drain valve. Open the temperature/pressure-relief valve. Drain two to three gallons of water. If the water is milky, drain entire tank.

Close the drain valve and open the cold-water supply valve. Open a hot-water faucet and let hot water run three minutes to make sure all the air is out of the tank before returning it to service.

Check the anode rod. This reduces corrosion and extends the life of the heater. You should have a plumber check the anode rod at least every three years, depending on local water conditions.

Please call the plumber.

aheavens@phillynews.com or write him at Box 8263, Philadelphia 19101. Volume prohibits individual replies.