[Motor31]

Running the tanks dry means you run out of the fuel before you run out of the smell additive. The smell doesn't burn when the fuel mixture is below optimum ratio. The solution is pretty simple, don't run the tanks down to full empty and let the pressure drop in the lines. The flame will go out on the stove but there is still residual gas, below the burning pressure and mixture that will escape. Once the pressure drops you then have to purge the air out of the lines to get things to run properly but there is still the smell additive in them. The detector doesn't detect the additive, it looks for propane. Your nose will handle detecting the smell though.