Fresh water tank question

[Floridafran]

Seeing the question about how full people travel with their FW tank reminded me of something that happened to us on our NC trip that I meant to ask about but forgot.

We started out in NC at Creekwoof Farm RV park (very nice place) and made sure our tank was full before we left for Black Mountain Campground (National Forest cg) since we knew it had no hook-ups. When we arrived, our FW tank was only about half full. Granted we had some pretty twisty and rough roads getting there but would that have caused the water to somehow slosh out through the overflow? Or did we do something wrong that we need to correct before we go on another dry camping trip?

Thanks for any insight you can offer on this. We have a 2011 Vista 30W, if that matters.

Fran

[Dadeaux]

I think you have another problem if you are sure it was full. Since gauges can error did you get your info from them or from observation?

[Wanabee FTer]

Here is a link to another thread that's talks about that same concern

[Gary CA]

Floridafran: I know when my freshwater tank is full because I fill until the water hits the ground from the overflow hose on top of the tank. The gauges provided with the coach are not accurate. I changed out my gauges with the Seelevel II, one of the best modifications you can do.

[Jerry J]

Quote:

Originally Posted by Gary CA Floridafran: I know when my freshwater tank is full because I fill until the water hits the ground from the overflow hose on top of the tank. The gauges provided with the coach are not accurate. I changed out my gauges with the Seelevel II, one of the best modifications you can do.

I fill til the water hits the ground also. It seems the gauge says it is full before it actually does. Maybe not a lot of difference but still a few extra gallons.
Was changing to the Seelevel very difficult? Did you just change the sensors and use the original wires? I've thought of doing this but just not at the top of the list yet.

[Floridafran]

Wanabee - thanks for the link. Lots of good info there.

I checked with my husband and he said he verified the tank was full visually so I think we may have experienced the siphoning that others mentioned in the link Wanabee gave.

We won't have time to do anything about it before we leave Wednesday, but fortunately we're staying in State parks with hook-ups so it won't be an issue this trip. We can just add this to the list of things we'll need to resolve before we head out West next year.

Thanks again for the help. Merry Christmas & Happy New Year to everybody.

Fran

[Clay L]

It isn't siphoning it's sloshing and the fix is a upside down U of tubing on the overflow that goes well above the top of the tank so it's difficult for the water to slosh out.

The overflow fitting is spin welded to the top of the tank and the tube does not extend into the tank so siphoning isn't possible.

You can lose some water from tank if it's filled too fast. The air can't escape fast enough and the tank expands. When you stop filling the tank it contracts back to it's original size pushing water out.
Opening the gravity fill door adds some extra air relief.

[AFChap]

It takes more than sloshing to empty most or all of a tank of water. I did not believe the "siphon" thing could happen either, until it happened to me. I lost most of a 100 gallon tank in a day of driving. I still cannot see how it can happen, but it does. That time I filled the tank to overflowing via the attached hose reel (there is no gravity fill), then disconnected and hit the road. I had maybe 15-20 gallon left when I got to my destination, estimated by physically viewing the side of the tank. Since that experience if I fill to overflowing, after the overflow stops I pull the fresh water dump valve for 20 seconds or so. I have never lost water again, by "sloshing" or "siphon" or whatever the phenomena is.

[skigramp]

I have lost a significant amount of fresh water from my tank through two errors that I discovered.

1) My outside shower was on just a little ... the compartment was very wet when I stopped at the end of the day ... a cup here ... a pint there ... pretty soon it adds up to gallons ...

2) I have installed a hose reel for the city fill ... the hose is attached to the city fill at all times ... if I do not put a male stopper in the female end of the hose it will siphon the fresh water tank darn near empty ... that has happened to me twice ... I soon learned to pay better attention to the stopper when I stow my fresh water hose ... so if your check valve on the city fill is not holding perfectly you could lose water out of that connection ... an easy fix for this is to go to Home depot and purchase a male stopper with garden hose threads. Screw that into your city fill until you get a chance to install a new check valve.