Venting the fresh water tank help

[vanster]

We are about to begin plumbing in our Caravel. We have a grey tank and a fresh water tank on either side of the axle. I have 2 holes on top of the fresh and 2 on the grey. For the fresh, one is for filling and the other is for the water pump. Did I forget to have a 3rd hole made? I am hoping I don't have to pull the tank out. Also what diameter is required for the vent?
Yes the floor is in ... 3/4 marine ply with cork flooring.

[Belegedhel]

So, yes, you need to be able to let the air out of your FW tank while you are filling it via the fill port. My '70's vintage has a fairly thin (maybe 1/2" diameter) tube at the top of the tank that allows air to escape from a port above the FW fill port. I suppose that if you filled your tank using a hose that goes down the fill neck and into the tank, then air could escape back out of the fill neck, and you would need no additional work, but then you run the risk of contaminating your FW supply with whatever might be on the outside of your filling hose. Maybe you could make the filling hose a permanent part of the set-up...

good luck!

[OTRA15]

As long as your fill spout (for the fresh water hose to go in) has a small hole in it next to the fill hole, you should be fine. You can probably buy an AS part that has this IMO.

http://airstreamsupply.com/Fresh-Wat...ck-gray-601194

Says out of stock FWIW.

SS for $188!

http://airstreamsupply.com/Fresh-Wat...s-steel-w-lock

[vanster]

Thanks,
Maybe I can build a something off of the filler tube just inside the exterior wall and run it down. We built weeping holes with clear plastic tubes at each corner of the window sills so if water collects it will have a place to go.
Van

[goshawks00]

I think your troubles may go farther than that. Once you do have water in the tank and you put your cap back on, you will have some difficulty pumping water out, as you will have a vacuum. No air vent to balance pressure in the tank as your pump 'sucks' the water out of it

[55AS]

Mine is above the floor and has vent and fill fittings at the top. Outlet (pump connection) is at the bottom. Since yours is below the floor, this may not work but if the tank is sealed you will not be able to pump properly due to vacuum forming in the tank.

[goshawks00]

On possible solution , depending on what your fill neck is, is to drill a small hole in your neck , run a tube down through that hole into the tank.

[gdanderson]

Our 67 Safari's filler cap is permentaly vented from the factory. We have no need for any tho of venting hose.

Greg Anderson
Wisconsin

[68 TWind]

That's interesting. The fill cap on my 68 does not have relief cuts in the factory cap. The tank I bought when I redid my trailer has 2 outlets on the bottom and a big fill outlet and small vent outlet on top. Not only will the pump strain and pull a vacuum on your tank if you have no vent, when you try to fill it from the filler neck it will "burp" back on you as the air in the tank has to go somewhere when it is displaced by the water. I plumbed mine so one bottom outlet goes to the pump and the other is connected to the city water side ( a couple of ball valves were needed) so I can fill the fresh tank any time I am hooked to city water and not mess with the filler neck on the outside. Also by opening one valve and closing a third ball valve, I can drain the tank.

[vanster]

This is really helpful. The original cap that is in the front is vented like the one Greg is showing. Now I can move things around or make a different cap...humm, lots of options

[A W Warn]

Originally Posted by gdanderson

Our 67 Safari's filler cap is permentaly vented from the factory. We have no need for any tho of venting hose.

Greg Anderson
Wisconsin

How do you keep ants and other small critters out of your water tank?

Is there a removable screen at the filler opening?