Black tank flush line

**Bluffrat361** · 09-10-2022, 09:42 AM

So I screwed up and am to blame for this leak. I was just finishing up camping and was flushing the black tank and thought it would be a good idea to hit it with full water pressure. Well I hit it way too hard and now I have a leak from the black tank flush to the black tank. My question is has anyone else had a leak here? And if so how hard was it to get to? This is a 2021 transcend xplor 265BH. Thank you for your help

**Hoopy Frood** · 09-10-2022, 09:53 AM

My thought would be that the vacuum breaker has broken.

They're just cheap plastic and it doesn't take much to break one. There are brass ones for sale and they are more robust. I wish I could tell you where the breaker is, but I don't know. I'm sure someone will be along that knows.

**Redapple63** · 09-10-2022, 09:58 AM

I agree with Hoopy, most likely a Vacuum Breaker (Air Valve).

It would be help to know which rig you have. On many for flush line the Vacuum Breaker is located behind the shower valve.

On my 315rlts, I can see it if I remove the wardrobe drawers on that wall.

Look on your rig behind the shower wall for some kind of panel to access it or behind something.

Good Luck

Bill

**RickLight** · 09-10-2022, 10:45 AM

My back flow preventer (alternate name) is under the bath sink. The only reason for putting in these spots seems to be so you notice if it leaks.

**Bluffrat361** · 09-10-2022, 11:57 AM

Originally Posted by Redapple63

I agree with Hoopy, most likely a Vacuum Breaker (Air Valve).

It would be help to know which rig you have. On many for flush line the Vacuum Breaker is located behind the shower valve.

On my 315rlts, I can see it if I remove the wardrobe drawers on that wall.

Look on your rig behind the shower wall for some kind of panel to access it or behind something.

Good Luck

Bill

This is on a 2021 grand design transcend xplor
265BH. What I did was I ordered a small camera to put down the black tank flush line to see if I can see anything. I will post results so if someone else has this issue in the future hopefully this thread will help. Thank y’all for the input

**NB Canada** · 09-10-2022, 12:10 PM

On another note I use mine at full water pressure. Mine works fine

**Redapple63** · 09-10-2022, 12:34 PM

Originally Posted by Bluffrat361

This is on a 2021 grand design transcend xplor
265BH. What I did was I ordered a small camera to put down the black tank flush line to see if I can see anything. I will post results so if someone else has this issue in the future hopefully this thread will help. Thank y’all for the input

On most of these rigs, it is almost a direct line to the black tank. The only other thing it connects to is the vacuum breaker between the feed and the tank.

Bill

**Hoopy Frood** · 09-10-2022, 12:46 PM

Originally Posted by NB Canada

On another note I use mine at full water pressure. Mine works fine

I also use mine at full pressure, but I open the faucet gradually. I did blow the top off one when I opened the quarter-turn ball valve too quickly one time, and the pressure was high.

**Bluffrat361** · 09-10-2022, 12:54 PM

Originally Posted by Redapple63

On most of these rigs, it is almost a direct line to the black tank. The only other thing it connects to is the vacuum breaker between the feed and the tank.

Bill

So the vacuum breaker pulls from the black tank flush or is there a vent that goes somewhere else?

**Redapple63** · 09-10-2022, 01:07 PM

Originally Posted by Bluffrat361

So the vacuum breaker pulls from the black tank flush or is there a vent that goes somewhere else?

There are certainly more of these, but I can tell you the black tank flush is isolated from the rest of the water supply. Runs direct to the black tank with the vacuum breaker somewhere between the inlet and the black tank sprayer.

Bill