A gasoline water heater has a pilot mild, a tiny flame that stays on normally to light-weight the burner once the signal is shipped from the thermostat. Prior to replacing a water heater thermostat, test it for continuity to be certain it's the culprit for the water heater not heating. https://letsbookmarkit.com/story17114224/5-simple-techniques-for-water-leak-from-water-heater