We expect hot water when we turn the tap handle and have become so accustomed to it that we rarely think about it. In essence it is just another convenience readily taken for granted.
Many of us have seen a recent television commercial depicting a water heater explosion. Although humorous in content and oriented towards loss recovery rather than prevention few of us have considered the real threat of a water heater explosion. It does happen!
The physics of such an event are easy enough to understand. When water is heated it expands. When it is contained pressure increases proportionately with heat. When pressure exceeds the containment vessel ratings; BOOM!
The optimum temperature of a water heater is 120 degrees. This temperature has been tested and recommended to prevent scalding. When properly adjusted a water heater will regulate the heating element to maintain this desired temperature. Note: Water heaters that supply home heat may have higher temperatures and should be supplied with tempering valves to prevent scalding at fixtures.
The first clue you may have to a water heater problem may be a noticeable increase in the temperature of the water. A higher temperature means higher water pressure inside the water heater tank and should be corrected.
An essential safety component of your water heater is the temperature pressure relief valve (TPR). Located at the top of your water heater, where the water is hottest, it is designed to release the hot water in the event that the temperature or pressure exceeds a predetermined safe level (typically 150 psi and 210 degrees F). Proper installation requires that the TPR discharge be directed through a pipe toward the floor and no more than 6 inches from the floor to prevent hazardous discharge.
By now you can see that a number of things must happen together to create an explosion. This can and does happen however, and your awareness should give you a new understanding of the need for qualified service when problems arise.
Independent Home Inspection examines water heater components, age and installation during your Home Inspection. Call for more information. 410-504-3751
visit me at http://www.IndependentHomeInspectionMD.com