Rheem Manufacturing Company MR50245 B

SaferProducts.gov consumer incident report 20170607-7684D-2147399883. Severity: Incident, No Injury. Product: Rheem Manufacturing Company MR50245 B (electric water heater). Incident: Once in 2014 and now, two Rheem thermostats failed closed on this water heater keeping the element continuously on creating scalding hot water dramatically overheating the thermostat area. In 2014 it was the lower thermostat and now it was the upper thermostat. I reported the safety concern about this overheating failure mode to Rheem in writing both in 2014 and now and asked whether the thermostats had been redesigned for a safer failure mode e.g. open circuit. Rheem failed to answer those questions and based on this recent second dangerous failure it's evident that they have not corrected the safety issue. I have photos of both failures including the charred heating element head in 2014. This time we detected the scalding hot water and I disconnected the upper element fed by the defective thermostat in time to prevent a possible fire. Today [REDACTED] from Rheem ([REDACTED]) told me that our 2 closed circuit thermostat failures were rare and usually caused by a electrical surge that welded the contacts closed. I told him that was not the case with us because we have a whole house surge supressor and no other device was ever damaged by any surge. He said Rheem uses the same bimetallic thermostat design everyone else uses with two exceptions for this plastic tank water heater; 1. They use a brass rod to transfer heat from the water to the thermostat 2. The Marathon thermostats are calibrated differently for the plastic tank