Originally Posted by chrismoore701
Another trick i heard about last year and it worked. Turn it on. Go out side and put your hand over the exhaust pipe. Wait for it to fire. Then you will be good. Blew my mind. But it worked. Give it a try
This is going to be wordy but here's my guess why this works (in my prior life, I was a fire investigator with the Michigan State Police)...
This trick prevents the LP that's filling an empty fuel line, causing it to initially enter the WH as a lean mix from escaping too quickly. When operating normally, spent or burned LP will exhaust out the port you are covering up to start the WH. You are artificially building a richer LP mix than would normally be present had the LP feeding the WH had a chance to flow at 100% fuel at thr beginning and not something less than 100%. It is less than 100% LP while in the process of displacing the air in the line between the tank and WH. Since the initial burn process involves a sputtering (lean mix) of LP until the line is "full," any natural draft that removes burnt fuel is also taking that lean fuel out with it, giving you the hard start. Your hand over the exhaust port is allowing a lean mix of LP to become trapped in the combustion chamber, hence richer, while the rest of the LP (or 100% flow) catches up to the WH. Some WH may be engineered to sense that lack of air flow you create with a hand over the exhaust port and defeat (or turn off) the WH until it is "corrected" as a built in safety measure.
The other option mentioned (starting a stove burner until it burns properly) will likely be easier for some, less work for others, drier for you on rainy set up days and probably safer. Personal choice though.
Perhaps, stand to one side of the WH as you cover the exhaust port. On a larger scale, I've had house fires I've investigated where I found the 40 gallon LP WH laying next to the house or up through the next floor of the home after an accumulation of LP gas sent them violently upwards after a spark or flame found the accumulated fuel. Fun times!