Bill.Satellite wrote:
It is so unlikely that the problem is the "disk" that I would simply discount that option. If you take something flexible and stick it up the outlet, do you run into an obstruction about as far up as the slide valve would be located? This is the most common issue (blade disconnected and not opening or opening properly). If this flexible object will go far into the black tank then you likely have a blockage (not the plug) and you need to deal with this right away. This is my favorite drain cleaning tool:
http://www.homedepot.com/p/BrassCraft-Medium-Drain-Bladder-BC00332/100586170
Open the drain, insert this into the opening, let it inflate and seal the opening and it will force high pressure water back into the tank. After a few minutes, turn off the water and close the valve quickly. This should get the fluids flowing whether you like it or not. (I like to tilt the coach away from the drain to minimize water flow during this operation). You may have to do this several (many) times to get a free flow but once you do you will have a good starting point to getting your tank clean and free flowing again in the future.
Bill, that WON'T work if the knife valve is CLOSED!...i.e. handle is broken or came off....Dennis
