Water Heaters

Most homes have their water heated by gas, oil-fired, or electric heaters. Tanks normally range in size from 30 to 82 gallons. Modern tanks are covered with a thin layer of enamel to prevent corrosion. Insulation is placed between the tank and the outer metal jacket to minimize heat loss and condensation.

To guard against excessive temperature or pressure, every water heater must have a temperature/pressure relief valve that automatically releases water when the temperature or pressure in the tank reaches its limit.

The temperature setting should be kept as low as is safe to conserve energy and prolong tank life. Water should be at least 110 degrees Fahrenheit to kill microbes and no more than 130 to 140 degrees Fahrenheit, to prevent scalding.

Inside some tanks, replaceable magnesium rods are suspended in the water to attract corrosive electrolytes that would otherwise consume the tank walls. These rods can be checked and replaced periodically; however, as a practical matter, this is rarely done.