We had an AO Smith GCV 50-300 gas water heater installed a month ago. It is working fine, but seems to be cycling on and off a lot more frequently than the old one did.
It seems that this short cycling results in the burner coming on more often, but not staying on as long, thus it appears to be by design, not a flaw.
The temperature is set to about 125, and that is the temp I am getting at the tap, so I know the thermostat is working.
I am just interested in knowing whether the short cycling is a feature or is a possible problem.
I believe this unit has the Robertshaw thermostat. There is a small black knob with a pilot light button below. You turn the knob clockwise to increase temperature. There is an LED light that flashes at a regular interval to indicate that the pilot is lit.