[NeBob]

We recently spent our first long weekend in 443. This morning when I went to dump the holding tank it is draining very slow. The dump valve sounds as if it is opening completely but afraid to disconnect hose and have a look see. Anyone ever have a similar issue? Could it be a build up in bottom of tank?
Should I add some kind of cleaner to tank and try again?

[pairodice]

It may be the Dupree Valve (the flapper thing inside the plunger thingy)... if you remove the top (two screws) you WILL get raw sewage everywhere!... you can unscrew the fitting (the 4" or so big screw that holds on to the coach end of the plumbing) while holding it tight against the coach end of the plumbing - it doesn't have that much pressure on it... then pull it away slowly to see if the plunger thingy is plugged. It will let you know pretty fast and you can screw it back on if needed. You might find a dumping spot or get a BIG bucket to catch the residue.

[folivier]

Bob, look in the passenger side basement compartment and see if you have a curbside dump?
If so you can hook up to that to dump and flush your tank until you get the main dump fixed. It may be an air powered dump valve and the switch would be somewhere on the dash or near the transmission buttons.

[NeBob]

Thanks for all the help. I found there was a second valve behind the pneumatic valve. It appears this is in place to allow the gray water to drain without dumping the black water. After opening the black water manual valve it appears as if it drained properly. I also flushed the holding tank to make sure it was clean.
Thanks for all the help.

[encantotom]

yup, we all knew that but didnt think to bring that up. that back valve is manual and is the main dump.

tom