Fun with black water tanks

[norty1]

Originally Posted by Bill Johnson

I think he's from Canada it might be a little cold up there to crawl under and check

No doubt about that!

[Yooper906]

Originally Posted by norty1

Well no it doesn't, but we are offering personnel experiences from real life. I don't know of anyone who knows since it has not been looked at yet. It will be interesting to find out what caused it!

I agree. I'm curious too.

[Bayoutalker]

I had the same thing occur last summer. We live in our RV so waiting wasn't going to happen. When I removed the bottom I found the tank had slipped out of the brackets and was hanging on the piping and the toilet inlet was open. Of course all nasty was on top of the tank. Luckily the tank wasn't hurt so I was able to clean up the mess and put it back in place. I re-bent the brackets and repositioned them to better hold the tank in place. I also bought some metal "plumbers tape" and added a couple of slings under the tank to help hold it in place. So far it is working fine with no leaks.

I agree, pull it apart as soon as possible. Jayco isn't the quickest with shipping replacement parts.

[bobsamm]

I did the same thing.my black tank blew up so much it came out of the mounting brackets. The vent pipe came off the top of the tank. The vent vent pipe is spin welded onto the tank. I put it back together with pvc cement. Have not had any leaks or smell. It has been 2 years.

[Mr Bee]

Originally Posted by spoon059

I was wondering the same thing. There should be no way to pressurize it. Either it should come out the toilet or the vent pipe.

Not sure how it would come up through a toilet since that has a one way flow valve / flap.

[mjeronimo]

Originally Posted by sberry1

At the end of last season, I made the unfortunate error of turning off the wrong water hose after flushing my black tank. I had closed the tank off and later heard a loud bang.

The tank no longer holds any liquid. Nothing comes through the drainpipe if I add water, it all comes out the bottom. I haven't removed the plastic cover on the bottom yet. It was the end of September and I had two weeks left before closure.

If anyone else has experienced this, what should I expect to find once I cut away the under-cover? I've been told a crack that can be sealed. Should I expect to need to replace the entire tank? Any insight into this would be appreciated.

Happened to my cousin they were flushing-loud bang water pouring out of plastic cover. Tank needs to be replaced. FYI don’t try to repair it will just fail.

[bheisser]

If you coraplastic that cover the bottom, you are going to want to try and remove it or cut a hole ( it is not that hard to remove, getting it back up will be a 2 person job), watchout when you do water liqiuid may poor out.
Check for wet insulation and remove/replace.
Or call you insurance about a 3k fix at a dealer

[CBR_Guy]

Here’s the sticker on my 2020 JayFeather 24RL. It’s kind of generic but I’m not sure that the black tank is vented to the roof—there’s no reason to. The sinks, yes, I have a vent for each sink but there are p-traps in the sinks so you need a vent. But it would only be an odor source for the black tank and if the toilet valve is open during flushing there’s no pressure reason to have a vent. Maybe I’m missing something (not the first time) but the warning is likely because the tank flush spray would over pressure the black tank if the drain valve or toilet valve weren’t open. Regardless, the black tank is likely split.

[Bill Johnson]

Originally Posted by CBR_Guy

Here’s the sticker on my 2020 JayFeather 24RL. It’s kind of generic but I’m not sure that the black tank is vented to the roof—there’s no reason to. The sinks, yes, I have a vent for each sink but there are p-traps in the sinks so you need a vent. But it would only be an odor source for the black tank and if the toilet valve is open during flushing there’s no pressure reason to have a vent. Maybe I’m missing something (not the first time) but the warning is likely because the tank flush spray would over pressure the black tank if the drain valve or toilet valve weren’t open. Regardless, the black tank is likely split.

If you look at post 13 on the previous page it shows a vent pipe on the black tank. I think they do it so on a hot day we don't end up with a brown face when flush the toilet and need to wipe down the walls. Some people posting on here have had that problem where it blows back at them because the tank is over full and blocks the vent or the vent itself is blocked

[Nature Ist]

Originally Posted by CBR_Guy

Here’s the sticker on my 2020 JayFeather 24RL. It’s kind of generic but I’m not sure that the black tank is vented to the roof—there’s no reason to. The sinks, yes, I have a vent for each sink but there are p-traps in the sinks so you need a vent. But it would only be an odor source for the black tank and if the toilet valve is open during flushing there’s no pressure reason to have a vent. Maybe I’m missing something (not the first time) but the warning is likely because the tank flush spray would over pressure the black tank if the drain valve or toilet valve weren’t open. Regardless, the black tank is likely split.

All waste tanks must be vented individually vented! Your black tank has a vent to the roof.
The warning on that sticker is primarily to prevent an overfill, which would push waste water where it doesn't belong. Though it wouldn't seem likely, using the tank flush, the pressurized city water supply will fill the tank rather quickly, especially if you are not using a pressure regulator at the hose connection. As the water reaches the top of the tank, it will first block the air flow out the vent pipe, forcing water to rise in the vent pipe, while also forcing water up the 3" waste pipe to the toilet. As the water rises, it will fill the cavity in the toilet base until it is above the level of the top of the toilet bowl. As that is happening, the toilet bowl will start to fill, and it will continue until the bowl overflows onto the floor. (The flush valve seal does not hold back the amount of back-pressure forcing the waste water up. ) During this process, the pressure and weight of the water in the filled black tank puts enough stress on the tank to cause a rupture. For those who have experienced this event, the "bang" is the sound of the tank reaching it's limit to resist pressure.
The warning to always open the drain valve is very appropriate!

[Captnjimk]

I have a 2017 Alante 26x. I heard that several fellow campers have hooked up a hose to the black water flush instead of the fresh water outlet. I overcame this problem by creating a short section of hose that remains permanently connected to the fresh water fill outlet. It is long enough to extend through the floor opening of the utility compartment. And I keep an on/off valve on this hose to keep bugs, etc out. When needed, I attach my fresh water hose to it. Easy solution for a BIG potential problem.

[Bayoutalker]

Originally Posted by CBR_Guy

Here’s the sticker on my 2020 JayFeather 24RL. It’s kind of generic but I’m not sure that the black tank is vented to the roof—there’s no reason to. The sinks, yes, I have a vent for each sink but there are p-traps in the sinks so you need a vent. But it would only be an odor source for the black tank and if the toilet valve is open during flushing there’s no pressure reason to have a vent. Maybe I’m missing something (not the first time) but the warning is likely because the tank flush spray would over pressure the black tank if the drain valve or toilet valve weren’t open. Regardless, the black tank is likely split.

My 34RSBS definitely has a vent. I saw it when I had to put the tank back in place. If there were no vent, on a hot day the smell would be unbearable when you flushed the toilet. You definitely don't want those gases to build up between flushes.

[Bill Johnson]

Originally Posted by Captnjimk

I have a 2017 Alante 26x. I heard that several fellow campers have hooked up a hose to the black water flush instead of the fresh water outlet. I overcame this problem by creating a short section of hose that remains permanently connected to the fresh water fill outlet. It is long enough to extend through the floor opening of the utility compartment. And I keep an on/off valve on this hose to keep bugs, etc out. When needed, I attach my fresh water hose to it. Easy solution for a BIG potential problem.

I looked up your motorhome and I see the two connections, they can be confusing. The top one being the fresh water fill and the bottom being the flush. If the cap on the flush connection was painted black or a black magic marker was used on the cap no one could make a mistake. I have a Brother P-Touch labeler and it really comes in handy for unmarked light switches. We labeled one of our slide outs so the wife remembers to move the seat forward before pushing the button. It would work great for your water connections

[CBR_Guy]

Thanks all for the correction on the black tank vent. That’s what I get for wading through the snow in the dark to get a photo…