Fresh water tank disaster

[iahawk]

Rockwood Mini-lite, 18 ft 2010 model
We just returned from Rocky Mt. Natl. Park where we had a major problem. I think I know what happened, but feedback is appreciated. Like many, I've had some problems filling my tank completely, with water shooting back as I try to fill it. When we got to the campground, at a little over 8000 feet above sea level, we started filling the tank. It shot back so I held the hose tight against the opening. After a bit, I asked my wife to hold the hose while I visually checked the tank. As I started to bend down to look, there was a loud crashing sound. The two support bars holding the tank failed, dropping one end of the tank to the ground. All four rails supporting the tank were bent and the plastic tank itself was bulged way out of shape. We drained the tank and I was able to remove the two support bars and prop the tank enough to drive slowly to the campsite. I got a number for an RV repairman from a friendly ranger. An hour and a half later (and $160 out of pocket), the guy and I were able to hammer out some of the bent support pieces and use a jack to raise the tank and replace the supports. We were able to bucket water in to fill about 1/3 of the tank and did that a couple times to get water, and did make it home to Iowa. Here, I discovered an insect had completely filled the air vent next to the filling opening. Here is my thought--going to such a high elevation, with the vent plugged, the tank expanded from reduced air pressure on the outside. I filled it, and actually overfilled it, causing the supports to bend and fail. Is this what happened? The tank, completely distended and bulging in the mountains, has returned to its former shape and looks fine. Does the filling spout not let the tank to vent properly, or is there a one-way valve in there preventing it from equalizing air pressure when the air vent is clogged? I'm taking it to have the bent supports replaced, since I don't trust the stressed metal. Having cleaned the air vent, I can now put water into the tank easily. In the future, I will ALWAYS check to make sure that vent is completely open. Comments are welcome.

[Windywest]

In my opinion, regardless of how full the tank was, the support bars should not have failed. I've seen some fresh water tanks and the tank inlet is usually on the side near the top, not on the top, so your tank is never completely full of water and has a thin layer of air inside that would equalize any pressure differences. You probably had a defective support bar, and when it gave away, the others followed.

[TURBS]

One thing about filling these tanks.
In most cases you have to trickle the water in . "Why you ask?"
You can actually put more water in then air escaping.
So what you get is a "air explosion with water"

It takes me almost 30 minutes to fill my water tank but I always get it full and I never get water blown back.

"Windywest" if you hold the hose up tight and rush water in the tank not allowing air out your going to expand that tank way out of shape and yes it is possible to blow those straps out.
Hydraulic pressure will bend or break things.

Op looks like you'll be needing a new tank and straps cause I guaranty you its all deformed now.

In the future slow and easy....
Besides "your camping" whats the hurry?

How do I know all this?
Dont ask.

"sabre owners united!"


turbs

[cabranch47]

I agree with Turbs. I tried to fill mine with the faucet wide open and even using one of those water fill tube things, overpressured it and blew out the side. Lesson learned.

[youroo]

By holding it tight,you just made a (BIG Water Balloon) out of your (Pressurized F/W Tank)! Youroo!!

[iahawk]

A big water balloon it was! Yes, and at my age "slow and easy" should definitely be my mantra
Thanks, folks. Too bad more learning doesn't come the easy way.

[TURBS]

Originally Posted by iahawk

A big water balloon it was! Yes, and at my age "slow and easy" should definitely be my mantra
Thanks, folks. Too bad more learning doesn't come the easy way.

You dont live to far from one of our favorite spots to camp.

Unfortunately a new tank and straps are in order.





"sabre owners united!"


turbs

[Windywest]

Everyday I learn something new here, I'll be filling my tank a lot slower in future.

[00buck]

The tank supports on my 21FBRS bent while filling the tank in the driveway. They are just not designed very well considering that they have to hold around 300 pounds. I had 1/4 angle iron welded over the old supports and also added 1/4 steel plates across the bottom of the tank.

Re the bug in the vent line. Was there no screen in your vent?

[iahawk]

00Buck, good idea on adding some supports. I thought I would take it back to the dealer and have them replace the existing bent supports, but just beefing up what is there might be the best way to go. As for the vents, no screen on the vent hole. Probably a mud dobber or some other kind of wasp had plugged it. I'll try to stick a little screen in there.