ATF: Bighorn - Fresh Water Loss

[BuckO]

We just took our new (2012) 3185RL out for its first dry camping excursion last week. Everything went very well, but we noticed one peculiar item. We filled the fresh water tank and headed to the camp site, when we arrived we only had 2/3 of a tank left. I was told by a friend that every time I went around a curve, enough water would flow from the tank vents to leave a trail on the road. I was wondering if other users or the factory have any suggestions to prevent the water loss.

Thanks,
Buck

 

[boatto5er]

Did the friend actually see this occur? More than likely the tank just didn't get full when you "filled" it. This happens a lot due to the way the fill hoses are run and other stuff. Also, if you were using the tank gauge to show the fill level, they are notoriously inaccurate.

 

[hoefler]

Very common issue for several years. As the water moves around in the tank as you drive, it will flow out the over flow. On our Landmark, I found we had 4 vents in our fresh water tank, one in each corner. We experienced the same thing, loosing most our water in 200 miles. We live where it is very hilly, and this was not going to work. While investigating why our water tank was falling out, ( another story in its self ), I made the discovery of all the vents. I removed 2 of the vents that went through the belly skin and installed a valve in the one I left in. When water flows out of the one remaining vent, I close the valve, and off we go. We arrive with all the water I loaded.

 

[BuckO]

Yes, I actually filled the tank to the overflow. Our friend was right behind us and saw the water coming out from whichever side was on the outside of the curve. Our rig has a vent coming out above the frame, one on each side. When I pulled into a shopping center I also saw the water flowing out of the vent as I made a turn. I was looking at my brother in laws Landmark and saw that his vent is run back to the UDC. This seems like a better arrangement and solves the problem. Only problem is I would have to drop the bottom insulation if I want to run it to the UDC to prevent possible freezing in the vent. I was hoping for a better / simpler option.
I appreciate any and all suggestions from other members! I will be investigating the underside options to see which way I need to go.

Buck

 

[hoefler]

It already has a vent running back to the UDC. If you pull the skin down you will be able to see all.

 

[BuckO]

It already has a vent running back to the UDC. If you pull the skin down you will be able to see all.

hoefler,
When I get back I will check again, but I am pretty sure mine does not have an additional vent in the UDC. The vents are by the wheels, one on each side. With the amount of water loss I had, I suspect the vents on the tank are on the ends of the tank and not in the middle top of the tank. If this is the case, a simple fix is to run the left vent to the right side and the right vent to the left side. This would have prevented the centrifugal action from pushing water from the tank. I was hoping the factory would give some insight, but have not seen a comment yet. Chances are I will end up pulling the skin down to look at it, probably will be very educational!

 

[hoefler]

The vents are in the upper 4 corners. If you look at your gravity fill in the UDC, to the left of the fill hole, there is a small, about 3/4" hole with a screen in it, that is the vent back to the gravity fill. That is the way it is on our coach, yours very well may be different.

 

[BuckO]

The vents are in the upper 4 corners. If you look at your gravity fill in the UDC, to the left of the fill hole, there is a small, about 3/4" hole with a screen in it, that is the vent back to the gravity fill. That is the way it is on our coach, yours very well may be different.

Hoefler,
Sorry for the late reply, I was in Las Vegas for a few days (Pronounced “Lost Wages”).
FYI, my system is the new pressure fill for the fresh water tank. That is why I am real concerned about not restricting the vent capability. I would hate to blow my tank apart!
I looked around the UDC and did find a vent near the fill connection, unfortunately the inside connection of the vent is not connected to anything. I then intentionally overfilled the tank to see if there were any other vents and could not find anything other than the vent on each side just above the frame.
I looked at the existing vents and believe I can extend the vents up about 2 inches higher without any interference with the slides. I need to make sure there is not any restriction to the vent, the water drains back properly so they will not freeze and make sure the vent is still pointing down to prevent dirt entry. This is what I am going to try for the short term. If I have to get into the “belly of the beast” at a later date, I will look at running the vent back to the UDC like it should have been done originally. I hope the factory is at least considering evaluating and / or going back to the previous vent system!
Thanks for all the help!!