Rheem XR90 Series Use and Care Manual - Page 21

Water Temperature Setting... Maximum water temperatures occur just after the burner has shut off. To determine the water temperature, turn on a hot water faucet and place a thermometer in the water stream. A condition known as "stacking" or "layering" can occur when a series of short and frequent hot water draws are taken. The hottest temperature water will be at the top of the tank, closest to the outlet pipe delivering hot water to the home. Stacking can cause this top layer of water to be hotter than the water toward the bottom of the tank near the gas control (thermostat). Therefore, always remember to test the water temperature with your hand before use and remember that hotter water increases the risk of scald injury. Also, always supervise young children or others who are incapacitated. The gas control (thermostat) is constructed with a built in safety shutoff device designed to shut off the gas supply to the burner if the main burner is extinguished for any reason. The gas control (thermostat) is also equipped with a gas shutoff device that will shut off the gas supply to the burner if the water heater exceeds normal operating temperatures. Refer to the "Before You Call For Service" section of this manual, or contact your dealer. ! WARNING: Should overheating occur or the gas supply fail to shut off, turn off the manual gas control valve to the appliance NOTICE: Replace any part of the gas control system which has been under water. If the water heater has been subjected to fire, physical damage, turn off the manual gas control (shutoff) valve and do not operate the water heater again until it has been checked by a qualified service technician. 140°F 130°F 150°F 160°F 120°F 113°F 105°F 98°F 90° F Temperatures are approximate Time/Temperature Relationship in Scalds Water Temperature 120°F 125°F 130°F 135°F 140°F 145°F 150°F 155°F Table courtesy of Shriners Burn Institute Time To Produce a Serious Burn More than 5 minutes 11/2 to 2 minutes About 30 seconds About 10 seconds Less than 5 seconds Less than 3 seconds About 11/2 seconds About 1 second 21