[Denr]

The solenoid is basically an electrically energized valve to control the flow of LPG to the burners. Most of them work with devises called sniffers that detect the presence of gas. If too much gas accumulates, the valve will be automatically closed. In the event of a leak or problem, without the valve, the gas would continue to flow and sink to the lowest level of the boat and could potentially explode.

I personally prefer CNG as it is lighter than air and would find its way out of the boat instead of accumulating in it. CNGs availability is its only drawback.