I have a 2016 Jayco 10sd. I have water in my fresh water tank, but can’t figire out how to empty it. I went to the area that says low point drain and there are no valves. I unscrewed the plywood covering the bench holding the tank and there was one valve that appeared to lead to the exterior. Turned it with no luck. I looked to see if the hole was clogged and it doesn’t appear so. Help!!