According to consumer affairs the Whirlpool WATER KING flame lock water heater has caused somewhat of a problem.The water heater , requires frequent maintenance and the problem is the device's thermocouple. The thermocouple is a standard part in water heaters that helps regulate water temperature.Normally a thermocouple will last 10-12 years or more. Many complaints has been Whirlpool Flame Lock water heater worked less than six months before the thermocouple broke, followed by repeated malfunctions even after a service repairman replaced the part.The problem is the thermocouple uses left-handed threading, which means it's not universal -- the customer must either get a replacement part by mail or try to find one at Lowe's.Left-handed threads are generally only used for propane. Homeowners  can prevent the thermocouple from malfunctioning by cleaning the flame-trap and combustion chamber every three months.According to the manual, cleaning the flame trap and combustion chamber also requires the owner to turn off and then turn back on the gas line to the water heater unsafe for most homeowners.