Could use local help - Kansas City

Hello all -

I just had my first overnighter in my "classic" RV.  A couple of months ago, I bought a 1975 19ft Nu Wa and have been in the process or renovating it. 

By and large things went well, with two exceptions.  First was the fridge which I talk about in another post.  Second was dumping my tanks. 

I tired twice to dump my tanks, the first before I got to my campground, and then when leaving.  Both times, it seemed like nothing was coming out.  At least the second time, I know there should have been something in both the gray and black water tanks.  I have read several instructions on how to do it, and thought I knew what I was doing.  So, there must just be something I am not understanding.  At best all that would come out is a slow trickle.  There are no monitors on these tanks so I can't tell how full or empty they are.

I am wondering if there is someone local who might be able to lend me a hand and see if I am doing this right.  I am down in Olathe, south of KC.      If you can help me out, you can email me direct at [email protected].

I suguest you ask the campground host for help. Most campers are more than willing to help each other. I believe all sewer pipes have handles uyou pull or push to open the valve.

Hope this helps.

If you do not get local help, here are a few things to try.

First of all, get a flashlight, hold open the flush valve, and, using the flash light, look in to determine what the level of sewage is in the tank.  That will tell you what the full nature of your problem is with the black tank.  The grey tank cannot be so inspected but it actually rarely has problems since it only has soapy rinse water for the main part.

You say you have instructions so you should know what the knife valves are, and how they work.  If not get a good book on RV stuff, Bill Estes' The RV Handbook is good.

Your black tank drain may simply be crudded up with old toilet paper and such. 

First of all, go to an RV parts store and obtain a clear plastic elbow with back flusher.  See example by click on HERE.  Hook it up to the tank outlet and to the sewer hose and hook the sewer hose to a sewer inlet.  Open the black tank knife valve, being sure that the gray tank knife valve is closed.    Hook the back flusher to a garden hose and the hose to a faucet.  Turn on the faucet full blast and allow to run for about a minute.  Turn it off and see what comes out.  Keep repeating until you feel that there is no crud left to  come out. 

Now close the black valve.  Using a garden hose fill the black tank to about 2/3s full thru the flush valve in the john -- estimate by looking down in the tank with the flashlight.  Open the black tank knife valve and let it drain -- you can watch progress thru the clear plastic elbow.  If everything drains ok you are back in business.

To prevent the black tank from getting plugged by crud in the future:

1.  Camp with the black tank drain closed.  The gray tank can be opened to the sewer but not the black tank.  The black tank will operate just as a septic tank to digest crud.

2.  Avoid the use of chemistry as much at possible.  The bacteria naturally in the tank will do the job.  Some folks add additional bacteria in form of products like Rid-x.  They may well help.    I dunno, I just let the natural bugs do the job.

3.  Use a toilet paper only approved for use in septic systems.  For one brand,  Scotts seems to work nicely and is widely available.  The expensive stuff you buy in RV stores is not actually, and has been a source of dissatisfaction around here, shall I say.

4.  Dump the black tank ONLY when 2/3s full.  That gives the bugs enough time to disintegrate things and the water pressure will give a surge to clean out the remaining crud at the bottom of the tank and in the pipe.  If the tank is not 2/3 s full when you want to dump, fill it with your garden hose

By the way, do not ever use your white drinking water hose for any of this stuff.  Use a cheap, colored garden hose.

Thanks for the advice.? The back flushing elbow looks interesting and I will order one of those up.

Some of the comments have lead to another question, and this may be the source of my problem.? ?Below is a picture of my valve assembly.? ?I have heard a few times about opening the black water tank valve first, then the grey water valve.

It seemed to me like the first valve (the one on the right) is the grey water valve and the second (the one on the left) is the black water.  My reasoning is that the blackcolored tank seen on the left is directly under the lavatory.  There are two pipes in sort of a Y configuration that connect to the large PVC pipe between the two valves.  One goes up to where the shower drain would approximately be and the other goes toward the rear of the RV towards where the kitchen sink would be.

So, wouldn't I need to open both valves in order to flush the black tank in the left of this picture?  Again, assuming that black colored tank is also the black water tank?

That's a strange valve configuration and I can't see enough of the piuping to be sure.  The black tank is normally a 3" pipe and the gray a 1.5".  They often come together and exit thru one opening, but usually both valves do not have to be open to dump either one. Yours look like one valve is in series with the other, though, so maybe both do have to be open at once.

Damned if I have seen anything like that!  All I can suggest is to trace out the connections from the toilet to the black tank, and from the kitchen sink to the gray.  Exactly how that is to be done I could not tell you without seeing it.  As Gary said, the black plumbing will be large diameter.  The standard is 3".  Gray is smaller since no solids are involved.  Standard for gray is 1-1/2#. 

By the way, black and gray water tanks should not be opened at the same time.  Black first, then shut black, open gray.  That procedure allows the soapy gray water to clean out the sewer hose after dumping the black tank.

Thanks for the feedback.  I feel a little better about my confusion.

I have sent an email to Nu Wa indsutries to see if there is anyone there who can shed some light on this.  I am hoping that this is not some system that somewhere along the way someone has tried to alter.

I am also going to crawl under the RV later today and get a snapshot from another angle that might be more revealing.

Thanks again.