Black Tank Flush Hook up seamed plugged up.

[English Lake Montana]

Hi. Today before winterizing I tried for the first time to flush out the lack tank using the fitting in the convenience center of my 2007 34RL that we purchased last summer. After hooking up the hose and opening the black tank drain I turned on the water full pressure but no water was reaching the tank. It acted like the line was completely plugged up. Any help would be appreciated. Also there seams to be a lack of instructions on how to use the convenience center. I found a great YouTube video on how to winterize if you are using antifreeze but none if you are using air to winterize. Again, this is for using the convenience center, not your regular type of rv plumbing setup.
Thanks
Ron

[twindman]

Most likely the flush line is plugged by the back flow device. It was behind the wall in my 2006 2980 model. In my mountaineer it was under the sink. My 2006 was fixed at the dealer - they cut a larger hole in the wall and fixed it and then covered it with a plate like thing.
Good luck.
p.s. I am pretty sure someone else will come along with more specific advice.

[rohrmann]

There is also the possibility that the previous owner had a problem with the flush system, such as possibly the backflow device failed, and instead of messing with it, just cut and capped the lines. This will take a little detective work to figure out.

[miamogue]

Another possibility is that the nozel is clogged. I had this happen. The holes on the nozel are really small and if the previous owner shut off water supply while the nozel was submerged some matter may have been syphoned into the nozel. I had to remove nozel from side of tank and clean it out. I also opened the holes a few thousands. No further trouble after that. On my trailer, I was the one who caused the jam so it can happen.

[biznsa]

I have an '09 3400RL and have quit using the black tank flush. Water would always start flowing out under my bedroom slide. I was told the backflow device was behind the shower wall. Not worth the effort to fix. Now, I just have my daughter stand on the flush for a few minutes after dumping to remove any left behind debris.

As far as the air, I use both. I blow with air and then use antifreeze. Up here in Northern Michigan, temps can get extreme in the dead of winter.

[DQDick]

For air I just attached the air connection (http://www.amazon.com/Camco-36143-Br...r+line+blowout), open the low point valves (small white valves in lower right of convenience center) and the faucets inside and drain what you can, then I put 30psi in the lines, closed the low point drains and opened each faucet again and flushed the toilet, then opened the low point drains, shut off the air and leave the drains open. Last I put antifreeze in each P trap and the toilet. If you have a washer/dryer you have to get antifreeze in there also so it's easier to just use the antifreeze method in total.

[Lkelly3400]

I had the same problem with my 2015 3610 RL the first time I used the black tank flush. Had the dealer check it, they said if there is too much water pressure the back flow valve restricts. Due to all the problems reported I now use Flush King to back fill the Black Water tank. Does a better job anyway.

[robebeckl]

I also had a clogged nozzel at tank.