black water tank for the toliet

[Bmwarnertrike]

why does the tank back up. in the tank itself. we have cleaned out and tank still is backed up. it is not emptying. it will not empty with the back wash on. causes and suggestions to fix.

 

[jbeletti]

Sorry to hear about your black tank issue. A couple of causes come to mind:
1. A blockage in the tank
2. A blockage in the pipe between the tank and valve or after the valve
3. A broken gate valve for that tank

I've listed these in the order of likelihood (my opinion).

You mentioned "we have cleaned out". What did you clean out, where and did stuff come out?

 

[JohnDar]

Are you using a back flush adapter on the sewer outlet? If so, does water flow back into the piping and tank or does it seem to pressurize and spew out the connection? If this happens, the valve has not opened. If water seems to flow freely, then there is no blockage (or you’ve pushed it back into the tank) and the valve is open.

It has been reported by other owners that the cutout from the opening for the toilet drain has fallen into the tank during manufacturing and has somehow lodged itself across the opening for the valve. Using the adapter I mentioned may force it out of the way.


Sent from my iPad using Tapatalk

 

[JohnD]

Also, if your black and gray drain out of the same drain hole you could use the gray water to back flush into the black tank to help dislodge anything blocking the black tank opening.

If you put one of these on your drain (it is a good safety measure to have to help prevent doing 'the brown shoe shuffle' and is only $25 at Camping World):



https://www.campingworld.com/twist-on-valve
(I will never own a camper without one of these)

I do this all the time!

Matter of fact, I'll be doing it this morning when I park my Prowler in storage until next time I go out (no campouts planned until Sept. as I just finished a 6-month run).

With the Valterra twist-on gate valve you can drain the black tank, then close the Valterra valve, but leave the black tank valve open, and with a good amount of water in your gray tank you can open the gray valve and the gray water will flow into the black tank.

You can hear it gurgling (or I put my hand on the drain pipe and feel it)...and when it stops gurgling...close the gray tank valve and open the Valterra gate valve and the water will come out.

I'll repeat this process several times until I don't see anymore 'stuff' coming out in the water.

I like to do this while the built-in black tank flush is running to help get the crud off of the bottom of the tank.

Hope this helps!

 

[Lou_and_Bette]

Don’t take this the wrong way but, are you determining the black tank is not emptying by the light indicators inside your rig? These sensors are notorious for being unreliable.

 

[Gary521]

why does the tank back up. in the tank itself. we have cleaned out and tank still is backed up. it is not emptying. it will not empty with the back wash on. causes and suggestions to fix.

What does that mean when you say that " We have cleaned out and tank still backed up"?