Sundance 241BH - Black water tank fell out

[bedpan]

Hey Folks,

Got a new 2018 Sundance 241BH. We picked it up a few weeks ago and just finished up our first trip. We drove from the Toronto area down to Cape Canaveral Fl. In total 5050km including some driving around down there not hooked up. The first day we pulled into the park I went about setting up and inadvertently connected the fresh water hose to the black water flush out. A few minutes later we heard a loud bang and shutter to find the black water tank sitting on the ground.

Fortunately the toilet had only been used for a couple emergency pee's on the drive south so there was no major mess to clean up. I was able to put everything back together and it all appears to be working fine.

What I am wondering is why the tank would fall out. As far as I can tell the tank pressurized and swelled. When it swelled it got narrower as it got taller and fell from the brackets holding it in place. There did did not appear to be a lot of water in there. Far less then the 30 gallons that it should be able to hold (saying that I am not positive though, maybe it was 30 gallons). The tank itself was not damaged at all the brackets holding it were not bent at all.

In my mind the tank is vented to the roof. Should the tank not filled to capacity then turned the trailer into a water feature spraying water out the vent? Is there some sort of check valve to prevent this?

What I am really wondering is there a venting issue that needs to be resolved now?

Any thoughts are appreciated.

As a side note I have not refilled the tank to capacity to confirm the brackets are able to support the weight. Due to our only being in Fl for a 5 nights I thought it best to leave it alone. Come spring here I plan on filling the tank to capacity to confirm it will not fall out. Also there the fresh water tank which is 44 Gallons has bars underneath it to support it where the grey and black tanks do not.

Side side note.. Seeing the tank laying on the ground it reminded me of this video "front of the boat fell off"

Why did the tank fall off?

[bedpan]

My thoughts as well, thanks wnjj..

I will have a discussion with the dealer at some point when I have sometime... The reality is it maybe easier for me to fix the vent, or add supports then the time it takes to hookup and drive 45 minutes up the road twice, to drop off and then pickup. Worth the discussion non the less..

wnjj wrote:

dougrainer wrote:
IF the OP is HONEST and tells the Dealer what happened, then odds are the factory will deny any warranty. It is not the dealer that makes the decision on covered warranty items, it is the Factory. The fact is, the OP did something wrong, and he should shoulder blame and cost. Doug

There's nothing wrong with filling the black tank with fresh water, even if through an non-standard means. The flow rate of the hose should be easily offset by the vent. If it cannot handle being full of water with 5 psi, it never will when travelling down the road.

[wnjj]

dougrainer wrote:
IF the OP is HONEST and tells the Dealer what happened, then odds are the factory will deny any warranty. It is not the dealer that makes the decision on covered warranty items, it is the Factory. The fact is, the OP did something wrong, and he should shoulder blame and cost. Doug

There's nothing wrong with filling the black tank with fresh water, even if through an non-standard means. The flow rate of the hose should be easily offset by the vent. If it cannot handle being full of water with 5 psi, it never will when travelling down the road.

[PaulJ2]

Lousy quality tank (too thin) followed by crummy installation. Thin walled plastic tank when filled causes bottom to sag downward, pulling in the sides, and then slips through the brackets.

[dougrainer]

IF the OP is HONEST and tells the Dealer what happened, then odds are the factory will deny any warranty. It is not the dealer that makes the decision on covered warranty items, it is the Factory. The fact is, the OP did something wrong, and he should shoulder blame and cost. Doug

[dougrainer]

tarnold wrote:
Because water tends to “seeks its own level” wouldn’t it back up the toilet first (lower) than the top of the vent pipe?

IF your toilet ball is OPEN then yes the water will come up in the toilet. BUT, the same seal that keeps water IN the bowl after flushing also stops water from coming UP. besides, the VOLUME and PRESSURE of the water is greater than any small seal leak in the toilet. RV toilets are NOT plumbed like residential toilets. Doug

[bedpan]

Thanks for the replies folks...

It comes down to 2 things for me. The tank was filling and it fell off. In which case I was lucky that it happened with 99% fresh water. This should be a warranty issue.

or

The tank pressurized due to a venting issue. It swelled and fell off. IN which case another warranty issue.

I had to repair in park as I did not want to loose access to the trailer trying to bring it to a random dealer to repair. Further I have 2500km to get home to bring it to my dealer.

I will touch base with the dealer and see what they have to say.

Cheers folks.

Mike

[tarnold]

Because water tends to “seeks its own level” wouldn’t it back up the toilet first (lower) than the top of the vent pipe?

[wnjj]

At only 9-10 feet vertical, it should take about 5 psi to drive water out the vent. That is hardly a lot of pressure. The tank should not have fallen out.

Fill the tank mostly full and then inspect the shape and mounting brackets. You don’t want a nearly full black tank falling out.

[dougrainer]

I just read the OP's post again.
NOT A WARRANTY PROBLEM. HOOKING UP TO A BLACK FLUSH AND OVERFILLING THE TANK WILL CAUSE SUCH PROBLEMS. BE THANKFULL THE TANK FELL OUT.
Otherwise, when you fill the tank with 45 psi and higher PRESSURE, the ONLY place for the water to go is UP the vent pipe. It takes a lot of pressure to push that water up the vent pipe. BAD news is, they rarely seal the roof hole where the vent pipe sticks out. When you overfill the Black tank with city water pressure and the water does come out of the roof, usually you have stinky colored water coming off the roof and most of the time the excess water flows into the roof ceiling cavity and floods the interior of the roof with the water/sewage coming out all over the place. I have had fresh water tanks overfilled by city water pressure fill and the customer blocked off the air vents to prevent a partial loss of water in transit and when the Fresh tank could not vent, the hydraulic pressure from the expanding tank has popped floor boards and bent brackets. Doug

[IB853347201]

John Burke wrote:
NEW trailer. Does not matter if you filled it with water or by using it. It still fell out.
Hello RV dealer, here is your problem. That is warranty is for. Do not fix or modify a new unit still under warranty.

X2!

[John_Burke]

NEW trailer. Does not matter if you filled it with water or by using it. It still fell out.
Hello RV dealer, here is your problem. That is warranty is for. Do not fix or modify a new unit still under warranty.

[Lynnmor]

There are no check valves, the vent pipe should simply go up and out. A common problem is the vent pipes fall to the tank bottom or were not installed correctly in the first place.

[bedpan]

As I do sometimes run with full grey/black tanks I was pondering putting some straps up. I was originally going to use some copper pipe strapping when I had it all open. Once I looked at the Fresh water tank, they used some additional 'L' shaped brackets running perpendicular to the mounts. I should be able to rig up something similar fairly easy...

Before I modify I want to know why it happened though. If the tank is swelling and I hook it up wrong again I may end up with more damage then the tank falling out if it has no where to go. The tank may burst or damage floor above it...

No I will NEVER make the mistake again. Saying that though I do lend out the trailer to a couple select family and friends.. Whos to say what they do!

OkieGene wrote:
I’d get some strapping to run completely across the bottom of the tank, at least 2 or 3.

The manufactured probably saved a buck seventy four on materials.

[OkieGene]

I’d get some strapping to run completely across the bottom of the tank, at least 2 or 3.

The manufactured probably saved a buck seventy four on materials.

[Old-Biscuit]

No straps/braces/supports across the bottom of tank
Those side supports just hold it in place but do NOTHING to keep a OVERFILLED tank in place

30 gallons-----250#
Tank changing shape

No wonder it fell out.....only reason you didn't have 'thar she blows' is cause it fell out


Best mod is to add full supports (angle iron) across bottom side to side