What causes the loud gurgling in old water heaters?

Just curious as to why an old water heater tends to get noisy?

Last one got so noisy from gurgling that it awoke me at night. The new one the plumber just installed (Bradford-White I think) I can barely hear at all.

My parents often changed theirs every 5 years, or so it seemed, due to noise.

Tia.

B~

Reply to
B. Peg
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You might not need a new water heater just a new anode rod every other year or new elements.

Occasionally, electric water heater users complain of hissing or singing noises from within the unit.

Actually, the sounds are being produced by the heating elements and occur for a variety of reasons.

Most water supplies contain minerals, which form a scale on the element sheath. The scale formation is

absorbent and eventually traps small pockets of water inside the scale. When the element heats, the trapped water

forms into steam resulting in hissing or other sounds as it is released from the scale. Other times, the heating

elements can act like a tuning fork and vibrate. The electrical current causes this vibration and the sound you hear is

called a 'harmonic vibration'. Tightening the heating element as little at ¼ turn often stops harmonic vibrations.

Although potentially bothersome, this condition is quite normal. Hot water is a complex environment that

enhances the existing capability of naturally occurring minerals to cause corrosion, scale deposits, and odor

problems. These minerals are already present in the cold water supply. In fact you can see the same 'lime' substance

build up around almost any water faucet fixture.

Heating water causes existing minerals to settle faster and in larger quantities. As the water is heated, it

becomes lighter and less dense. The naturally occurring solids, although not visible to the eye, will settle at a faster

rate. The result is sediment collecting at the bottom of the tank. Routine draining maintenance will help reduce the

collection of sediment. If a homeowner does not periodically drain and flush the tank, the sediment will continue to

accumulate on the bottom the tank. The result is a clogged drain valve and scale build up on the electric heating

elements.

In areas of low water pressure (usually under 30 pounds per square inch gauge), it is not unusual for water

heating elements to make sounds. Spot boiling at the elements, which would not normally occur at higher pressures,

causes the noise. Under these conditions, the noise is normal.

Voltage in excess of that stamped on the heating element flange can cause a noise. As voltage rises above

the elements rating, wattage is increased. The element is doing more 'work' than it is designed to do and may be

vibrating from the increased resistance. Check your water heaters rating plate for the properly rated element size.

Generally, heating elements should not be replaced when the water heater makes a little noise. Most noises

do not signify an unsafe condition. Check for lime scale on the element, sediment in the tank, low water pressure, or

abnormal voltages to the water heater.

All of these checks involve contact with hot water or electrical voltages. Use caution when diagnosing

noise complaints.

If in doubt, call a water heater or plumbing professional.

Reply to
Ned Flanders

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