This was another challenging project. The water heater was not heating up beyond 70 degrees. The gas was apparently shtting off early despite the max setting and I determined that the thermostat in the gas valve was not functioning properly. The dificulty started when I discovered that the valve was no longer available from the manufacturer. after a couple days of on line searching, I found a new, replacement valve and now the customer has piping hot water again.
Cost: $425 inc valve