Common problems with a Rheem water heater include a lack of hot water and incorrect water temperature. Problems and solutions vary based on the type of water heater.
Issues which can cause a lack of hot water include a lack of electrical power, using too much hot water or the temperature pressure relief valve discharging too much water. Electrical problems may come from the power cord being unplugged, an issue at the switchboard or a timer that shuts off the power supply.
The amount of water that can be heated varies based on the size and model of the water heater. Using too much hot water or using too many appliances with hot water at one time can reduce the water flow. The temperature pressure relief valve releases water during the heating cycle. If it discharges too much water -- more than approximately one bucket in a 24-hour period -- the relief valve needs to be serviced. When the water temperature is too hot, it may be due to a faulty temperature limiting valve.
If the water heater doesn't have a temperature limiting valve, the thermostat can be adjusted downwards to lower the temperature. Rheem has a network of independent contractors who consumers can contact for repairs and part replacements.