Why doesn't water overflow my gravity fill tube?

[phays]

I needed to fill my fresh water tank on my 98 Vectra and hooked the hose to the city/fill connection, set the valve to fill the tank. My owners manual says to continue to fill until water comes out of the gravity fill tube. Unfortunately, no water came out of the gravity fill tube but did come out somewhere under the coach. I suspect there is a vent tube on the fresh water tank and it does not extend as high at the gravity fill tube which would allow the water to come out of the vent tube.

Am I correct in thinking there is a vent tube that the water came out of?

[phays]

I needed to fill my fresh water tank on my 98 Vectra and hooked the hose to the city/fill connection, set the valve to fill the tank. My owners manual says to continue to fill until water comes out of the gravity fill tube. Unfortunately, no water came out of the gravity fill tube but did come out somewhere under the coach. I suspect there is a vent tube on the fresh water tank and it does not extend as high at the gravity fill tube which would allow the water to come out of the vent tube.

Am I correct in thinking there is a vent tube that the water came out of?

[Petro]

Phays;

I believe you are correct. When I over fill my fresh water tank, water runs out under the coach. I suspect it is a vent tube as well. Maybe someone with more info will pop in here.

Don

[PeteB]

There is an overflow tube that exits under the coach and will drain off overflow if the inflow from the fill hose isn't too much for it. If the inflow is more that the overflow can handle the water will back up into the gravity fill hose and out. I learned the hard way as my compartment door was open and the gravity fill overflow ran inside the compartments..
Pete

[Harry B]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If the inflow is more that the overflow can handle the water will back up into the gravity fill hose and out. </div></BLOCKQUOTE>

I also learned the hard way that the tank overflow has a limited capacity to shed water when full. Contrary to the tank overflow, the gravity fill hose and opening offer no resistance with about a 1" diameter and that is where the excess water in the tank will go if the tank overflow can not keep up. Unlike Pete, my cover to the gravety fill opening was closed, but there are openings in the gravety fill housing that the water will go through and into the basement compartments.

Now when I want to top off my water tank, I make sure that the compartment door below the gravety fill opening is closed and that the gravety fill door cover is open. This way if water does migrate out the gravety fill opening it goes out and on the ground and not in the compartments below.

[codgerbill]

Today(Sunday)I was sanitizing the fresh water tank. I did the bleach thingy and filled the fresh water tank. I began to see water coming from under the coach. At first I thought I might have had a ruptured hose/pipe . I opened the dump (drain valve on the fresh water tank) and as I watched the level in the fresh water tank thru the translucent tank material I did see the water level start to come down and the water from under the coach stop coming out. It dawned on me that I had overfilled the tank when I could finally begin to see the water level as the tank emptied. I was filling using the fresh water fill tube just aft of the entrance door on the passenger side.

[Mike Finnerty]

That darned gravity fill tube strikes again. I have had two problems with the tube on my 2003 Sunova. First when it was new, we had a flood in the bedroom after driving to a campground with the water tank reasonably full. It turned out, that the tube had a large cut in it that allowed water that backed up into the tube to escape into the bedroom as we went up a couple of considerable sized hills. The second I discovered after the coach sat for a while. Again we had lots of wet carpet in the bedroom. I found that rainwater runoff from the roof was running down the side of the coach and finding its way around the access door to the gravity fill tube. The seal on the door that covered the tube opening did its job of keeping the rainwater out of the water tank. However, the water would collect inside the door and eventually fill to the level of the slot for the door latch and then into the coach. I determined this by a high water line left behind after the water level somehow went down. I have subsequently sealed shut the door to the gravity fill door to eliminate future occurrences.

[phays]

I pulled the plumbing diagrams from the Winnebago site and see that there is a vent tube on the fresh water tank. At this point I think we all agree that the vent tube was where the water overflows when filling the fresh water tank.

Thanks all for your responses.

[sightseer 30B]

If you want to rely on the overflow tube (not the gravity fill) to determine that the tank is full, I suggest that you ensure the overflow is not blocked.
At the end of the tube is a plastic screen to keep bugs out. On mine, the screen became blocked by floating plastic crud from the tank. It is easy to remove the screen by just pulling with a twisting motion.
If the overflow tube is blocked, the water will eventually go up the gravity feed tube. If the cover door is closed, pressure will build. This potentially will loosen the clamped-on flexable tube (or damage it). Not only will you have water in the interior from filling, but like Mike Finnerty said, sloshing of the water in driving will push water up the gravity tube and possible leak out of the damaged/loose hose.

Had to remove the bedroom cabinetry to put my hose back on. I feel your pain Mike. Been there. Mine was a 2004 Sightseer 30B. Dry for now.

[DAN L]

on my 35u, the gravity fill port is above the front storage door just behind the entry door. when filling the water tank with a pressure hose connected to the city water connection, make sure that the gravity fill door is open and that the storage door is closed. even with the storage door closed, you can get a lot of water in the storage compartment because there is a small opening in the gravity box where the latch latches. you must monitor the under coach overflow and the gravity fill port (open door) when filling the fresh water tank to keep from flooding the storage compartment. don't ask me how i know this.

[Chief]

After my first experience with the overflow tube allowing excess water to escape I have always used this indicator to alert me that the tank is indeed full and to shut off the water.

Never had water overflow into the compartments. Just lucky, I guess.