If you only have one switch inside, it is for gas.
The switch outside is for 120v operation.
You can use one, the other or both for quicker recovery.
Be SURE your water heater has water in it BEFORE turning on the 120v switch.
It will burn out the element if it doesn't have water in it.
wmtire will be along shortly with several good links to water heater operation.
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel-Goodyear Endurance Tires
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