Water Tanks Draining

[CaliforniaMade707]

I am trying to figure out how to fill up my water tanks on my 91 Fleetwood flair RV. When it is filled it drains out all of the water right away like the valve isn't working properly or I don't know how to shut at the proper way if anyone can please help???

 

[jackiemac]

Hi and welcome to the forum.

I'm sure someone will be along with an answer soon.

 

[Rene T]

Do you see the water draining out as youre filling? Can you send us a picture of the valve?
Now you said the water tanks with a S. You should only have one FRESH water tank. Now are you talking about the gray and black tanks? If you are talking about the gray and black tanks, is the water coming out of the 3” sewer drain pipe?

 

[Larry N.]

If you stop filling at about 3/4 full or so, does it still drain out? It's possible that you are overfilling it and, once it starts overflowing, it siphons out the rest of the tank.

 

[lynnmor]

When filling a tank that has a vent, also known as an overflow, there will be no such thing as a siphon action.  The vent attaches at the top and the flow will stop as soon as the filling stops.  We can't see what you have from here, can you post photos?

 

[Rene T]

When filling a tank that has a vent, also known as an overflow, there will be no such thing as a siphon action.  The vent attaches at the top and the flow will stop as soon as the filling stops.  We can't see what you have from here, can you post photos?

That?s partly true except when the vent hose sticks down into to tank and either by over filling and the line gets filled with water or we?ve seen when going around a corner, the line fills with water and if the line outlet is lower then the end of the line inside the tank, water will siphon out. I?ve heard that some people have had to put a valve on the end of the vent line and once they get to their destination, they just open that valve. Cheaper than tearing the rig apart in order to get to the top of the tank to address the line into the tank situation.

 

[jackiemac]

New members need I think 5 posts before they can add photos.

 

[lynnmor]

That?s partly true except when the vent hose sticks down into to tank and either by over filling and the line gets filled with water or we?ve seen when going around a corner, the line fills with water and if the line outlet is lower then the end of the line inside the tank, water will siphon out. I?ve heard that some people have had to put a valve on the end of the vent line and once they get to their destination, they just open that valve. Cheaper than tearing the rig apart in order to get to the top of the tank to address the line into the tank situation.

I have been all thru that craziness, first there is never a vent line that sticks down inside a tank and secondly it ain't a siphon.  A port at the top of a tank with a hose attached will of course spill out water when the tank is tilted or the trailer is rounding a curve.  Just a stupid and cheap design, the answer it to vent a tank well above water level.

Some will put valves on the vent line(s), but that is not a good idea for a tank that can be pressure filled.  I have warned numerous people to not do that only to have some destroy there trailers with the expanding tank.  Here is just one example:
https://kzfamilyforum.com/thread/3229/messed-big

 

[Ernie n Tara]

Meanwhile the question remains; is the drain shut off? There may be two drains and it/they may be just a cap(s) on the drain pipe or a valve that is accessed from inside the rv.

Ernie

 

[House Husband]

Typically Fleetwood mounted the 1991 fresh water tank behind the rear axle and over the frame. Look on the passengers side storage compartment for the drain valve. It is probably a small gray "T" handle valve with less than a 1/4" opening.

Richard