Water Heater Overheats

Problem: Water heater doesn’t shut off, causing overheating.

Background: An overheating water heater may cause boiling noises to come from inside the tank, steam to pop from hot water faucets, or hot water to back up into the cold water supply. (See Water Heater Makes Noises for causes of other water heater noises.) Normally the temperature-pressure (TP) relief valve protects the heater from excessive temperatures and pressures. However, it may have been improperly installed or become defective.

 

What to do: If a runaway water heater is suspected, turn off the burner and use a thermometer to check the water at a hot-water faucet. (Some heaters may be equipped with an automatic gas shutoff sys tem actuated by high water temperature.) If the reading is above what the setting on the heater should produce, the heater’s thermostat may be defective. Reset it if necessary; if that doesn’t help, call a technician. After the tank has been allowed to cool, check to see that the TP valve is working.

Special advice: Hot water presents a scalding hazard that varies according to the amount of time exposed and age of the persons involved. (Scalding may occur at different temperatures for children, elderly, infirm, or physically handicapped.) The Consumer Product Safety Com mission recommends water temperatures be kept at 1300 or lower.

Helpful hint: If persons potentially subject to scalding hazards are present in your home, or if local codes require a certain water temperature, lower the temperature setting as low as possible to meet your needs. Also consider installing some type of tempering device, such as a mixing valve, at hot water taps used by at- risk people, or at the water heater.