[jsmith948]

On our Suburban water heater, the control circuitry for the propane igniter is 12V, there should be a switch on your inside switch panel (ours is next to the water pump switch). The gas and 120v ac can run at the same time. If you are dry camping, or for some reason lose the functionality of the 120v heating element, simply turn the 12v switch on. We seldom use the electric side of the heater, but did use it in conjunction with the gas for a quicker return when our grand daughters were with us.