Is this a gas water heater or an electric one?
If it is electric, forget it. Just get a gas one.
If it is gas, make sure it is set up for propane and not NG.
Get a long lighter, like the one used to light a fire.
Light WH when you want. Turn off when you don't.
Pretty simple. . .
The valve won't last a long time doing that because they aren't made to be used as a manual on-off control. They are designed to be automatic.
Disclaimer: I do NOT endorse doing this! There is no provision to shut off the gas when the water reaches critical temp (and pressure) and if you have never been around when something with water firmly contained at or above 212 degrees is suddenly let go, you are lucky!
It is NOT something you will want to experience.
The pop-off valve should keep it from exploding, but again, there will be lots of water at very dangerous temperatures!
If the WH will NOT be indoors, you could replace the automatic valve with an appropriate manual valve, and rig in a barbecue grill spark ignition.
Then turn on gas, ignite, wait til hot and turn off.
Doug
