Received my replacement valve today. I am debating whether to install the new valve or leave the older style control valve/thermostat in. The old valve is working fine. The only thing that I see that I do not have with the old valve is the resettable thermal switch wiring that is on the new valve. The thermal switch never had to be reset so I did not have a problem with that. What exactly does the thermal switch protect against and do I really have a major safety issuse with the old valve? I don't see that it is any different then the previous water heater that was there for years without any problems. I still have the flash back screen in place and have not made any other modifications.