fresh water tank air vent

[CindyH]

I've replaced my old metal tank with a new polyethelene one. I need to put in an air vent and have a threaded opening for it.
My question is
How can I finish it on the outside so that its exterior opening looks good.

Cindy
1960 Traveler

[uwe]

Originally Posted by cindy

I've replaced my old metal tank with a new polyethelene one. I need to put in an air vent and have a threaded opening for it.
My question is
How can I finish it on the outside so that its exterior opening looks good.

Cindy
1960 Traveler

Cindy,
I am assuming you are talking about your fresh water tank?
If so, there is no need to vent it to the outside, as there should not be an odor or gas problem. You can vent the fresh tank with a hose that terminates above the tank and higher than the filler tube by a few inches. you can use rigid PVC pipe, if you have room, or flexible tubing, if you need to hide it behind installations, or a combination thereof.
The tank vent will prevent burps when filling, and provide smooth draining. It also keeps the tank from forming a vacuum, thus allowing water delivery to the pump when the faucets are on.
You might add a small screen type material to the end of the hose, like very fine mesh screen material to keep the occasional bug or piece of dirt out of the vent tube.
Good Luck!

[markdoane]

Uwe,
Thanks for the info. I'm doing the same replacement. Is there any concern about sloshing in the tank causing expulsion from the vent? I was kinda thinking about routing the vent tube through the floor and bellypan.

[thenewkid64]

Originally Posted by markdoane

Uwe,
Thanks for the info. I'm doing the same replacement. Is there any concern about sloshing in the tank causing expulsion from the vent? I was kinda thinking about routing the vent tube through the floor and bellypan.

Don,

I would be concerned about the possible overflow form the vent. I know on all of my trailers and Motorhomes when I fill the tank there is a fair amount of moist air and sometimes water that shoots out the vent tuber in the filler box. I would be comfortable about dropping it through the floor, but I would have a vent stack on it. Come off the tank to a T One leg goes thru the floor, the other is in the interior, above the top level of the tank. If you don't vent it and get a good slosh it could start to siphon out some of the water.

On the trailers that I have seen converted from the air over water system there is normally a small, less than 1/8 inch, hole drilled in the threaded cap that screws on the outside filler tube. It is big enough to allow air to enter as needed, but too small for bugs. This is what I would do, and just cap the threaded fitting.

[markdoane]

Brett,
Good idea, I hadn't thought of the siphon effect.

[uwe]

You could easily use an overflow bottle of sorts, to catch the occasional burp through the vent line. A modified windshield washer bottle would catch mist and water, sending it back into the tank after the eruption.
The asiset way out woul dbe to add a fitting to the top of the filler tube, just before it goes through the inner skin, and add the vent fitting there. After all, that is how it is from the factory.
I think routing it through the floor would cause foreign objects in your drinking water supply, sooner or later, or at least add another maintenance point to the whole shmier.

[DavidsonOverlander]

Originally Posted by markdoane

Uwe,
Thanks for the info. I'm doing the same replacement. Is there any concern about sloshing in the tank causing expulsion from the vent? I was kinda thinking about routing the vent tube through the floor and bellypan.

The vent tube in our '64 Overlander goes out the top and then down through the floor and bellypan.

Grant