This fresh tank siphoning is killing me

[Bullitt6283]

Originally Posted by oldmanAZ

If that one vent in the fill port doesn't have enough capacity, you may rupture your fresh water tank(s) when filling so fill s-l-o-w-l-y.

Venting air doesn't require as much port size as venting water.
.

[sirrealone]

What has usually worked for me to curb the siphoning is to lay off the water pressure as you reach the fill point. When I was putting water in at full pressure, it would drain for a good couple of minutes after I turned it off, even if when I turned it off at the first sign of overflow. But if I dial back the pressure toward the end, it dripped out for 10-15 seconds at most once I turned it off.

[TCNashville]

Originally Posted by sirrealone

What has usually worked for me to curb the siphoning is to lay off the water pressure as you reach the fill point. When I was putting water in at full pressure, it would drain for a good couple of minutes after I turned it off, even if when I turned it off at the first sign of overflow. But if I dial back the pressure toward the end, it dripped out for 10-15 seconds at most once I turned it off.

I find this to be true as well. I installed a flow meter on my fill hose and when it shows 75 gallons I slow it way down. [80 gallon FT]. As soon as I see a drip I shut the water off and probably don't lose 1/4 gallon. Of course this is while stationary and since I never travel with water this works well. I do have plugs for my overflow tubes if I ever decide to boondock. https://www.amazon.com/Rainwave-RW-9...n%2C151&sr=1-3

[Carmen]

Appreciate all of the info about fresh water tanks. But I have a new issue. I pulled into a fill station hooked up the hose to fill the tank, set the switches on the uni- doc to fill and it would not allow any water to go into the tank. It is a 2018 jayco 5th wheel RSTS. Any suggestions as to what the issue might be.

[us71na]

Originally Posted by parallax

I lose about 2/3 of my fresh water when I travel This leaking is driving me crazy. I am going to try using one way check valves and see what happens. My fresh water already has a vent hose at the fill port so hopefully this doesn’t end up being a bad idea. Any thoughts ?

Those will stop any and all water from coming out, but will let air in if that is your goal.

[Edpare]

I’m a little confused because there are more than one TT being discussed here. I have a 2-day old 248RBSW with the Rocky Mountain package of 2 tanks. I noticed the tanks were full when I left the dealer and down a third shortly after arriving one hour later at my RV park destination. I was not aware of the siphoning problem so I didn’t look for leakage. My TT has gravity fill on the left, two overflow tubes on the right and one gauge. Is there a fix for this?

[oldmanAZ]

Fresh water tank siphoning occurs in MANY (most? all?) RVs. It's not truly a 'leak', but it is a water loss out of the vent tubes when traveling.

There is more than 1 fix: I use 'corks' in the vent tubes; installed when traveling and removed when camping. Others use valves they close when traveling and open when camping. Other re-route their vent hoses to loop up high and back down to stop the siphoning.

There are MANY posts on this topic.

[DrSmart]

New to us North Point. Is this an overflow with a shut off to prevent siphoning for the fresh tank. There is another white plastic shut off mounted on a bracket near the door side that we were told was the fresh water drain. I have yet to figure out what this blue pex is for. The low point drain valves are enclosed.

[us71na]

Originally Posted by DrSmart

New to us North Point. Is this an overflow with a shut off to prevent siphoning for the fresh tank. There is another white plastic shut off mounted on a bracket near the door side that we were told was the fresh water drain. I have yet to figure out what this blue pex is for. The low point drain valves are enclosed.

That blue pex looks like a road debris catcher. Don't run over any plastic bags, wire or hunks of tires going down the road.

[RetiredOne]

Originally Posted by us71na

That blue pex looks like a road debris catcher. Don't run over any plastic bags, wire or hunks of tires going down the road.

and I thought it meant he had a Male trailer...

[TonyCO]

UPDATE

Took her to CW for some more warranty work. They performed the Jayco recommended fix by adding a few loops in the tank. I was able to get 60 gallons in with no problem. It started to blow out the overflows so I let it rest a few minutes and then continued to fill very slowly. 70 gallons was all she would take. Then I took it for a drive. I did notice water out of the overflows, but it did stop after 10 minutes. So I guess I will put the valves back on and just be happy.

Yes Doctor, I believe that is the overflow with a valve to prevent siphoning.

[JesseS]

1st trip with the 3 vent hoses on valves, filled to 75 Gal, turned them off, arrived at camp spot in the Tahoe basin (read lots of hills), and still had a full tank, where as the last trip I lost 20% out the vent lines due to sloshing on steep grades, this works for me so I will go with it.

[Tom and Dee]

Has anyone used a check value and if so do you have a part number.

[madmaxmutt]

Originally Posted by TonyCO

UPDATE

Took her to CW for some more warranty work. They performed the Jayco recommended fix by adding a few loops in the tank. I was able to get 60 gallons in with no problem. It started to blow out the overflows so I let it rest a few minutes and then continued to fill very slowly. 70 gallons was all she would take. Then I took it for a drive. I did notice water out of the overflows, but it did stop after 10 minutes. So I guess I will put the valves back on and just be happy.

Yes Doctor, I believe that is the overflow with a valve to prevent siphoning.

Tony,

Did your trailer have this flat tubing?



Mine is in for warranty work right now, but a couple weeks ago we filled up at Mueller. By the time I got the spot, we had lost over a third of the tank. It continued dumping on the ground for several minutes. I felt like just putting a clamp on the tube

I am not sure what the dealer will do about this, but if it continues I will figure out a valve for it.

[TonyCO]

No, mine is regular tubing. I would think they could add some tubing inside the tank too. It made a big difference for me. I would call the service guy and tell him to add it to the list. I emailed Jayco as well and they actually set up a pre-authorization based on my complaint.

[madmaxmutt]

Originally Posted by TonyCO

No, mine is regular tubing. I would think they could add some tubing inside the tank too. It made a big difference for me. I would call the service guy and tell him to add it to the list. I emailed Jayco as well and they actually set up a pre-authorization based on my complaint.

Thanks man! Yeah, I added it to the list when I found out Jayco sent them the wrong part for the work they were already doing. I think that flappy tubing may just be an extension of some kind. If whatever they do doesn't work, I will be dropping the belly cover and doing something myself with a valve.

[JesseS]

This is what I did to fix the issue, the hoses were already long enough to reach the back of the wet bay, so I installed the valves and the clear drain tubes so I can easily see when they start to overflow.

https://www.dropbox.com/s/j5m0fdts53..._3283.jpg?dl=0

[AKMX]

I installed this on the overflow/vent hoses for my Seneca. Cured the water loss problem while driving and the valve can be reached with the compartment doors shut. Also while the doors are shut the PEX cannot be seen from the outside.

[madmaxmutt]

Originally Posted by AKMX

I installed this on the overflow/vent hoses for my Seneca. Cured the water loss problem while driving and the valve can be reached with the compartment doors shut. Also while the doors are shut the PEX cannot be seen from the outside.

Excellent work! Looks like a knee saver to me.
You may have several copies in the near future.

[parallax]

I’m using one way check valves They were cheap. eBay has some at 3 bucks each. They are 12mm so just a tad under 1/2 inch. There a lot of manufactures out there mine came from China So far so good.