Fill fresh water and it siphons out

[Semix-Hex]

It this normal? Was it overfilled? Solutions?
The tank empties through three lines.

Thank you in advance.

[ARoamer]

Common problem. Search and you'll find lots of info. I guess I'm lucky, mine only siphons from one 1/2" line. I put a shutoff that stays open unless syphoning, then opened at campsite.

[CAG]

Shut off valves on all over flows but you have to put a note on your check list to open them before filling the tank or you expand the tank and blowup things.

[Rustynuts]

Many threads about it, mine would drain down to almost half empty. Like some said, you can add a valve but to me thats just asking for trouble....forget to open it when you set up camp and you can collapse your tank and forget to open before you fill can expand and pop the floor up, its been reported here.


Then best thing to do is to build an air gap to break the siphon, it doesnt take much, Many ways of doing it.

https://www.jaycoowners.com/forums/f...ing-54340.html


https://www.jaycoowners.com/forums/f...ons-66946.html


https://www.jaycoowners.com/forums/f...ank-54228.html

[dxrobertson]

Yes "normal", but only because its common and ill designed.

No, not overfilled.

The problem is 2 fold. As you fill the tank with the high pressure of city water, near when the tank is full, the water flows out the overflows, ok; but then this high pressure (with no air) creates the siphon. The other issue is the shallow tank and once filled and as you travel; the water sloshes around and escapes out the overflows.

It helps to slow the fill flow once the tank is nearing full, hopefully not creating the siphon.

And the standard fix for many of us as others already mention is to install shutoffs at the overflows. These are open when filling (make a note, as @CAG states!) and once overflow, turn off supply water and quickly shut the valves. Then open when at camp and using on board water (I only open 1 valve at camp).

[CAG]

Originally Posted by Rustynuts

Many threads about it, mine would drain down to almost half empty. Like some said, you can add a valve but to me thats just asking for trouble....forget to open it when you set up camp and you can collapse your tank and forget to open before you fill can expand and pop the floor up, its been reported here.


Then best thing to do is to build an air gap to break the siphon, it doesnt take much, Many ways of doing it.

https://www.jaycoowners.com/forums/f...ing-54340.html


https://www.jaycoowners.com/forums/f...ons-66946.html


https://www.jaycoowners.com/forums/f...ank-54228.html

I had valves on the cyclone for 11 years and never had “ trouble”. Put it on your checklist and much like flying don’t skip your checklist and yo are fine. Ignore the check list and pay the price.

[Semix-Hex]

Originally Posted by Rustynuts

Many threads about it, mine would drain down to almost half empty. Like some said, you can add a valve but to me thats just asking for trouble....forget to open it when you set up camp and you can collapse your tank and forget to open before you fill can expand and pop the floor up, its been reported here.


Then best thing to do is to build an air gap to break the siphon, it doesnt take much, Many ways of doing it.

So, yesterday, I was posting instead of thinking. I believe it was the heat of the moment i.e. packing up, ready to travel and water flushing out like no tomorrow.

After looking at the three lines all siphoning and reading a couple of lines, I ran one line to behind my fuel inlet as an air gap. 30 minutes to extend the line and tested. So far so good.

Thank you all for the help.