Hot Water Heater Switch

I have quick question about my water heater.

My owner's manual says that my water heater is propane only and there is no cotter pin switch on the outside control panel.

However, there is a small black on/off switch on this panel that has no cotter pin (it's just a basic rocker switch). What does this switch do? Can I leave this switch in the on position when I'm not using the water heater?

The on/off switch on the inside works fine, what is this other switch for? It seems ridiculous to have to go outside to flip a switch and then come inside to flip another switch every time I want hot water!

Thanks for any info.

Mac

The black switch on the outside is the 110 volt switch, used when connected to power. When in the "On" position and with the TM plugged in, the heating element is activated. The inside switch is used for propane use.

Note: When plugged in and with the outside switch "On", your hot water heater will work. It has a built in thermostat to only heat the water as necessary. You just leave it in the "On" position, you don't have to turn it on as you require hot water.