Flushing without opening dump valve

[Lazyboy]

I dump the tank. Flush with valve open. Close valve and flush for 30 to 60 seconds. Open valve drain tank. Repeat 3 or 4 times until liquid clears up. You will need a clear connector or elbow for your viewing pleasure

[vcbice]

Originally Posted by Packerbacker_TX

I've read some black tank horror stories and it sounds like you dodged a bullet on this one. Good thing it wasn't used before you got distracted. I suppose it's possible that there's an overflow drain at the top of the black tank that adjusts for this - just in case.

There is no overflow drain for this. The water just keeps going up until toilet overflows or it leaks out the vent pipe at the roof (or out the seams of the vent pipe). Neither is good.

If is is actual sewage you need to get in there and sanitize the areas where it leaked. If the vent pipe leaks at the tank you should get it sealed.

[Octane Shane]

I recently had a similar situation. I emptied my black water tank at night, left the valve open snd ran the flush. I turned the flush hose off, waited for the sound of water in the drain hose to stop and closed the drain.
I forgot to disconnect my flush hose lime I normally do, but you would think it's fine because I turned off the wye valve. Well, after eork the next day I came home to clear water running underneath the camper. What I eventually found was that the wye was still trickling water into the flush hose that I forgot to disconnect.
I later realized that tbe vent pipe had pushed upward and knocked off the vent pipe cover. The vent pipe is still currently about 2 inches higher than it should be.
How do I gain access to where tbe vent pipe connects to the black water tank? I'm rather certain that I need to reconnect the vent pipe to the tank.