My water heater is only five years old. The error code for cleaning the burner screen lights up, then the burner won't fire up. I shut it down , restarting it after few hours. It work for few hours , then same thing happens, same error code lights up, the burner won't fire up. I repeat the same process, and get same result, I replace the burner assembly, same thing happens. I also replace the gas control valve , same thing happens. Just don't know what the problem is