Mystery switch

Thats the challenge of RV ownership. Figuring out what everything does without destroying it in the process.

Sounds like a big blowtorch or small jet engine when it lights. Love that sound. When you turn that switch to "ON" the switch should glow and a small dot of a light should also come on. When the heater lights successfully, the little dot will go OUT and the light in the switch will say ON. At least the Atwood water heaters I've seen... Some of the older ones DO have a 120-VAC heating element that's hidden on the back (inboard) side of the tank. If you find another mystery switch (ours is a household wall switch with a light that says you've turned it ON), then you may have electric heating also. We can look that up, if you find and post the Model Number.

A couple of gallons should be fine- plenty of room to expand upwards. I might worry about the inlet fitting.

Darn, I was sure it was your garbage disposal.;)

X2 on the water heater switch. See if you hear it "whoosh" when somebody turns it on. The whoosh is the light up.

all part of owning a rv,you,ll learn some thing new each day.

Thanks.
I had to go outside and double check the heater was gas only.
I no longer have a mystery switch, and I'll get hot showers!
Now I just hope what water was left in the tank didn't damage anything.

Welcome!
Yes, that's the water heater switch. Having just one switch it activates the gas function.
Unless you turned it on and left it on without any water in the tank, you should be fine.

Oooops!!:o

Hope I didn't fry anything while trying to figure it out. Then again, I may be either saved or have worse issues. While putting a new mattress in the back, I noticed frost on the tank. When I pulled the drain plug, I got a couple gallons out of the tank.

Atwood water heater switch.