You may also choose to turn your hot water heater off completely. This will start the flow of gas to the pilot. How to Get Rid of the "Check Engine" Light Engineering You can turn off power to the water heater by switching off the breaker. How to turn off gas water heater for vacation . Steps before going on vacations and turning off the main water valve: Turn the gas control knob to pilot and press it downward. If you don’t have a vacation setting on your unit, manually change the temperature to between 50 and 70 degrees. The times you should turn it off, is when you will be away from home for an extended period. Instead of turning off your water heater before you head out, put it on “vacation” mode instead. If you carry out maintenance work on the water heater, including removal of sediments, it would make sense for you to turn off the heater during the cleanup. Also, when you turn off your water heater when on a vacation, you only meet more problems. ...