[Wingrider214]

We have a 2012 3400RL that we bought used just over a year ago. When I connect a hose to the flush port for the black tank, water will not flow into the tank. Seems like there is an obstruction somewhere. I have filled the tank and added cleaner several times hoping to clear anything at the port of the tank. I am assuming there is some type of check valve on this line. I am looking for options to fix this problem without opening a hole in the underbelly.