Originally Posted by Nightbrew
Thanks is the excess flow valve in the honeywell or built in to another piece?
It's built into the tank adapter. I think the older style tanks had them built into the tank valve. It's designed to slow the gas flow down to a trickle in the case of a supply hose breaking or other similar event. It doesn't shut the flow off completely in order to allow you to find the leak. To prevent the valve from tripping there has to be some back pressure against it, so if you have all of your high flow burner valves wide open and then turn the tank valve on suddenly, it could activate. If you partially close some valves downstream, it should build up some back pressure, and re-open.