Taken from the HWS Manual for Units with an Electric Element
Warning - Never operate the electric element without water in the tank.
Connect water supply
Turn OFF gas supply to the water heater
Ensure water heater is connected to a 240V outlet/power source
To energize the electric heating element, turn the switch to “ON” by manually removing the safety interlock pin inserted in the switch knob.
Set the switch to the “ON” position and reinsert pin.
The switch is located behind the water heater door in the
lower left corner of the control housing.
This procedure is necessary so as to prevent 240V element and gas heating from
operating simultaneously.
Happy Caravanning