Fresh water tank overflow dumping

[Jerald61]

Went out for a few days of camping in the 2015 WH 27DSRL, fresh water tank was full and I was connected to city water with a pressure regulator. Each morning temps where about 45 to 55 degrees, when I would get up and go out there was allot of water on the ground like something was leaking right under the overflow and low point drain for the freshwater tank. Drain valve was in closed position. I checked inside to make sure nothing was leaking from plumbing and all was dry. Outside temperature was in the mid 70's one afternoon when I was returning to the trailer city water was off and I see water coming out of the overflow slowly. Could this be a sign that the one way valve is failing or is there something else going on? Is the plumbing the same as this diagram? Help please.

[Rustysocket]

In a general sense I thing your diagram is correct but your fresh water tank is going to have an overflow and a vent I believe as well. It's not sealed completely as it would quickly develop a vacuum if it didn't.

When I stuff mine full it will overflow at various times. I attribute it to the poly tank shrinking / expanding rather than anything else.

If the check valve was failing you would be overflowing all the time when hooked up to a pressurized city line. The simple way to check it would be to drain your tank and see if it fills when connected to city water and if you have the valve station like some of us do your valve would be set to the city water setting .

I may have confused you as some of the newer rigs use a docking/valve station

[Jerald61]

Ok Rusty that sounds good to me, poly tank expanding and contracting and the tank was pretty full I think. I was at a high elevation don't know if that has anything to do with this cause it's not doing the leak at home, no city connected. Im going to stuff it tonight and connect a hose to city and see if it will leak in the morning. No docking station on my rig just connection to the city supply with hose.
Thanks

[bansai]

There are also a TON of posts on here about the overflow system draining excessive amounts of water if you move your camper while the fresh water tank is full. Some say it's the 'siphon' effect, others have their own reasons. All I know is if I fill my fresh water tank to the point where the overflow comes into play - the system doesn't just drain a gallon or so of water, it will drain half my tank if I don't step in.

I lot of people have installed their own shutoff valves on the overflow hoses that they close after filling their tanks, and reopen at other times. I'm doing that this spring. It's kind of lame to dump 20 + gallons of fresh water on the ground for no reason.

[Jerald61]

Wow that's hard to picture a siphon getting started unless the overflow goes deep into the tank. Yep I hear you dropping that much fresh water is a bad thing specially if you go boondocking and when you get there you don't have the amount of good ole H2O you had where you filled it!! I like the sound of adding a valve to the overflow..

Thanks

[Coldfusion]

Originally Posted by bansai

There are also a TON of posts on here about the overflow system draining excessive amounts of water if you move your camper while the fresh water tank is full. Some say it's the 'siphon' effect, others have their own reasons. All I know is if I fill my fresh water tank to the point where the overflow comes into play - the system doesn't just drain a gallon or so of water, it will drain half my tank if I don't step in.

I lot of people have installed their own shutoff valves on the overflow hoses that they close after filling their tanks, and reopen at other times. I'm doing that this spring. It's kind of lame to dump 20 + gallons of fresh water on the ground for no reason.

I installed shut off valves last season. As soon as water starts coming out I close the valves then travel to where I'm going and once I'm level I open the valves for venting. Best mod I've done so far and easy. Never lose water.


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[33 RLDS]

I was in the same boat. Lost half my water driving from the fill station to my site on the first trip out the camper. I extended the overfill lines and cap them when tanks are full and water starts pouring out of them and uncap them when i'm set up at the site. Never had a problem since.

[Jerald61]

Hey Coldfusion and 33RDLS
Before the caps and valves did you have water come out after you were level at your site and have been sitting for a day or two?

[bansai]

Originally Posted by Jerald61

Hey Coldfusion and 33RDLS
Before the caps and valves did you have water come out after you were level at your site and have been sitting for a day or two?

Well, for me anyway, no.

The overflow would stop puking water after about 10 to 15 minutes. This is if I fill up at a spigot in the campground, and then have to drive let's say another mile to get to my spot. If it was still puking water after a full day, your tank would be dry. It seems to stop way before that, but it can still cut your water storage in half.

[Jerald61]

Yeah I have the same thing happen like you but I've never stood there to see how long it drains I thought it stops in a few seconds or so. I did not have time to fill last night so I could see if it would come out in the cold morning like it did camping. I see all the post with this overflow problem. Be nice to see how far the overflow goes into the tank.

[Coldfusion]

Originally Posted by Jerald61

Hey Coldfusion and 33RDLS

Before the caps and valves did you have water come out after you were level at your site and have been sitting for a day or two?

None at all


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[Jerald61]

Well Im back on forum but have not had a chance to see what's causing my intermitant tank drain. But here's something don't know if it caused the tank draining unless it happened after I was leveled up. OK, when I got home from trip I noticed the rear stair was closer to the ground then normal, I thought maybe I have the jack high up front did not think about it anymore, now inside I saw some things out of place to the right side that had not moved before on the road still I paid no attention to this figured road bumps. Few days later went to cover tires and left side went on easy as before but the right side was hard to get on they were hanging up on wheel well fenders, this was strange. While sitting watching the tube a light came on in my brain and I started putting all these not normal things together. So went out took measurements along left side frame to ground and same on right side, the right side was 3 to 4 inches lower than the left, tires are good. So I go under TT to see what's up, what I see on right side is the leaf springs are flat straight across the hangers, left side still have a slight curve. Called dealer to see who does the warrantee on this Jayco or Dexter, they told me to send pictures, I did but did not get a call back I'll call them in the morning to see who takes care of this. Anybody else have these springs go flat?

[Jeff chavez]

I have a question.
Can I keep my 2 low point valves closed when I’m on city water ..I have them open now and periodically
They drain water . Just got my RV . It’s a 2017 Jayco flight 34RSBS

[Rustysocket]

Originally Posted by Jeff chavez

I have a question.
Can I keep my 2 low point valves closed when I’m on city water ..I have them open now and periodically
They drain water . Just got my RV . It’s a 2017 Jayco flight 34RSBS

When RV'ers speak of low point drains they are usually talking about the drains for the piping in the RV. These need to be closed whenever you are using the water system whether on city water or using your pump for you freshwater tank. Jayco confuses the issue because they mark your freshwater tank drain location on the side of the RV with a Low Point Drain sticker also (at least on my unit). This valve can either be open or closed when you are on city water (and have your valves configured to do so). If you are getting water draining out your freshwater tank drain valve while on city water you likely have a check valve that is failing on your pump. Especially if it is constant flow. If it is just a little bit occasionally it can be caused by flow by the check valve when the system is pressurizing and I would not worry about it.

If the check valve has failed your city water connection will eventually fill the freshwater tank and water will come out the tank overflow line continuously. If this is not happening you likely do not have a problem.

I hope this helps.

[Jeff chavez]

Thanks for the info
I monitored the amount of drainage
At night nothing . During the day time about a gallon drains out . Going to adjust my city water pressure valve and monitor it today . I live in a 210 space park
Not sure if the water pressure in