Loosing Water From The Fresh Water Tank

[timk]

Just a little update. I got a little further in toward the water tank today. Its only about 6"-7" tall, and when you consider the vent hoses are a little ways down on the sides, its ez to see why all the water splashes out. I'm all about plugging them lil buggers, now for sure.
Timk

 

[Ken Washington]

For those of us that only carry enough water to flush the toilet on the road, this is not a problem. I can't see hauling that much weight with fuel prices the way they are unless I am going to a place with out water. Not much chance of that!

 

[timk]

For those of us that only carry enough water to flush the toilet on the road, this is not a problem. I can't see hauling that much weight with fuel prices the way they are unless I am going to a place with out water. Not much chance of that!

Ken,
On a trip from the left coast back to Tucson 400 odd miles or so, we started out with the guages claiming 1/3 tank of fresh. When we got back to Tucson we were sucking air, barely able to get a flush.
TimK

 

[Ken Washington]

Hi Timk,
If we put a cut off on this, can it stay closed when filling the tank? What is the purpose of this vent anyway?

 

[timk]

Ken,

Its my understanding that there are 4 vents, I can see two of them, three out the bottom of the coach and one just beside the fill cap. I dont understand why we would need more than one vent. Someone else has posted here that a vacumn is created if water is used from the tank for more than a couple of days.

I am going to fill my tank this weekend to see how it fills and emptys, with the 3 vent valves closed. Will keep you posted. My last rv had only one vent and it worked just fine.

Our tanks are quite short but very wide. Perhaps if you were parked out of level so the primary vent is under water level a vacumn could be created when using water, but I wouldnt think it would take much for the water pump to overcome the force and just pull some air in.

TimK

 

[cdbMidland]

My unit has the drains and I thought that all water had been drained last fall when we winterized the unit. However, when I reached Florida a few days ago, I was surprised at the amount of water that was leaking out the drain at one of the rest stops. Must have been frozen in there. Fortunately, nothing seems to be broken, although I have not tried to add water to the fresh water tank.

 

[dap]

I don't quite understand the need for so many vents. I would think that one vent run upward to the exterior of the coach would suffice.

 

[cdbMidland]

I finally added water this morning in preparation for some self-contained camping in the Everglades. Everything seems to be fine. I only filled the tank until the monitor showed it was full and no problems showed after driving 130 miles.

 

[timk]

Plugging vent lines loosing water again update

I finally got the time to test the filling of the tank with the lower three vents plugged. Here are my findings.

One of the things I wanted to do was better understand how much water in gallons are represented by the little lights on the water guage. Inquing minds want to know, kind a thing. So what I did was to put a stop watch on while filling up a five gallon bucket and then doing the math. This is what I found while filling my water tank.

1/3 tank should be 24 gallons it was 10.3 gallons.
2/3 tank should be 48 gallons it was 29 gallons.
Full should be 73 gallons it was 53 gallons.
Full to overflowing vents it held 71 gallons.

I am not a 100% about the 73 gal. capacity but I think this is what the spec is. And I wouldn't bet the farm on my accuracy but its sorta close. This explains why when I thought I had a third of a tank, I ran out too soon. And as you read on it also explains why when your full, you use just a little water and all of a sudden the guage says 2/3.

The interesting thing is the full sensor is located where the water level would be if the vents (4) are open as the factory has installed them. So if you fill your tank till the vents start to flow water then wait till they quit leaking there is about 1-1/2 to 2 more inches of tank above the vents that cannot be used if the vents are open. At this level I hold about 53 gallons.

So being the clever fellow I am, I think plugging the vents and just filling her up is the thing to do. Well,............ It exploded the tank. Naw just kidding, wanted to see if your paying attention. But what it did do scared the holly you know what out of me.

At 73 gallons the tank had sagged about 4 inches below the frame and underbelly. I was under the rig while it was filling, so I could watch the water level, and I could feel it sagging down as more water was added.

After opening the 3 lower vents a little air came out but not too much. And that baby looked about 8.5 months pregnant. Thought it was going to fall off. And it did hold 73 gallons.

So in conclusion, when filling I wouldn't fill with the vents closed. One vent dosent seem to be enough. If you have it full, and dont want to loose your water when driving, I would then close the vents. And, next time you fill your water tank take a little peak underneath before you fill up. Then when your tank is full, take another lil peak and see how many months along you are. Mine is getting an extra brace or two.

TimK

 

[cdbMidland]

Looks like the factory needs to change its specs or revise the way the fresh water tank is designed and mounted (or both).

When I first bought my unit, I had the dealer "fill" the tank (probably to the full light on the monitor). I took it to a CAT scale and had it weighed with Saundra and me and the water. We were over the GCWR for the Dodge by just a few pounds.

I then left the scale and emptied the tank and reweighed. I was surprised that the weight did not decrease by the 580# that I figured that I had drained, but only by less than 400#. I just figured that the tank was not as empty as it should have been. Now I know that I should not have figured on the 70 gallons that showed on the specs.

The one thing that I was really interested in was the weight on the truck rear wheels by weighing empty and "full". The rear wheel weight only changed by 20# - the rest on the trailer axles. This is what I was hoping for as we never travel with anything in the waste tanks and only a few gallons in the fresh water tank (for toilet flushing and hand washing).

 

[Scott]

Water Specs

TimK and all:
The fresh water system in an RV is typically rated at the approximate number of gallons of fresh water that the unit can hold - and that INLCLUDES not only the tank, but also the water heater (12 gallons on a Landmark and Bighorn).
It's not surprising that when you attempted to put 73 gallons into the tank alone, it swelled the tank considerably.
On the issue of tank monitor panels/sensors - the fact is, this is not an exact science. I wish it were - because this is a situation that I bet I've heard more about from customers over my 20+ years in the RV manufacturing business than any other.
I wish they made a tank monitoring system that is exact. If they did, and it was affordable, we would have it. The truth is, KIB has dominated the RV market for these for years and they are in approx. 90% of RVs.
On the issues of overflow vents - on fifthwheels and travel trailers, the holding tanks are very shallow - and the bigger they get, in reality, they are just getting "wider", not deeper, so the issue of water sloshing around and going out the overflow vents is one that is inherent in shallow tanks. I think some of you have made good suggestions regarding your solutions to the problem and maybe one of them may be something we can look at implementing here at the factory.
Keep the dialogue open and going. Good ideas are needed in both these areas and to change an industry - it starts with the end user and that's you.
Until then, if Heartland is doing something wrong or needs to do something better - keep us informed.

ST

ST

 

[BillB800si]

[quote
We were over the GCWR for the Dodge by just a few pounds............

The one thing that I was really interested in was the weight on the truck rear wheels by weighing empty and "full". The rear wheel weight only changed by 20# - the rest on the trailer axles. ).[/quote]
-----------------------

Which model Bighorn were you pulling and whats the specs on your Dodge?
Very interested.

Thank you,
Bill B. (Michigan)

 

[timk]

Bill,
Our water tank is approx. centered over the rear axle. So full or empty I wouldnt expect much change in pin weight.
TimK

 

[timk]

Scott,
I hope my input was not received as negative. I'm all about making my rig the best it can be, and understanding whats going on in the secret world under the floor. And if my noodling around can help someone else to do the same, well I guess thats why I'm messing around here.
TimK

 

[BluegrassMan]

The water tank SAGA

Hi All:

I just had a thought would a check-valve work in the vent hoses. What I mean is like a plastic tube with a ball in it. If the water tries to go out the ball seats tight. the water can't pass by. When the pump draws water it NEEDS vacuum, the ball would float up and let air come in the vent. When the demand is over the ball goes back to the seat.

It seemed simple yet does the job. That's me simple

 

[timk]

Hi All:

I just had a thought would a check-valve work in the vent hoses. What I mean is like a plastic tube with a ball in it. If the water tries to go out the ball seats tight. the water can't pass by. When the pump draws water it NEEDS vacuum, the ball would float up and let air come in the vent. When the demand is over the ball goes back to the seat.

It seemed simple yet does the job. That's me simple

I think there are two things going on here. Filling the tank and using water.

Check valves should work fine when using water, (in my opinion).

I'm still a little worried about filling without the 2nd, 3rd, and 4th vent. When I did my test, filling my tank with only the vent by the fill hose open, (the lower 3 closed) my tank really swelled up. Not much air or water was venting out of the air vent by the filler. When I finally removed my garden fill hose, a ton of water puked back up from the filling opening. Presumably due to the ballooning effect of my tank. The bottom of my tank deflected about 4" from a flat position. So if everyting was equal in your rig, with a check valve allowing air in but not out, your tank might just swell up and sag as well. I dont think I would want to repeat what I did.

Right now I would still recomend a valve that could be opened when filling, and closed when driving. Or open when using water if a vacumn creates a problem.

I am going to add a cross member under the tank from frame to frame, to better support the tank. Then repeat the test. I will post my results.

TimK

 

[timk]

Problem solved

Just another update.

After adding the additional cross brace below my tank, I repeated the fill test to see how much water I can squirt into my fresh tank without blowing it up.

Here is what happened.

1/3 on the guage held 10.2 gallons, about the same as before.
2/3 on the guage held 28.2 gallons, about a gallon less.
Full on the guage held 51 gallons, about a couple gallons less.

The little bit less is to be expected and seems right due to the fact that the tank is now holding its shape and not swelling.

The above was done with the rear 3 vents open. I continued filling till there was a full flow of water from the 3 rear vents. The tank now held 66 gallons. Still no tank swelling.

I then closed the 3 rear vents and continued filling till the fill opening started to run over. I am now at 75 gallons and no swelling.

An interesting thing I noticed, when I closed the rear vents and continued filling, I noticed no air escaping from the remaining vent by the filler opening up front. So I still have to think the rear vents need to be opened again after the water level has gone down past the full level.

I'm done now
TimK

 

[elwaller39]

You say you added one cross brase to the bottom of the tank. How large of a cross brase was this and was this through the center of the tank? I would hope this would tell a story to Heartland to add another brase to support the fresh water tank. I too would like to have 70 gallans of fresh water when I fill the tank. I do not think that this would add that much additioal cost to a coach and to know your fresh water tank is not going to go bad in time from over filling it! Evans & Lana

 

[timk]

Evans and Lana,
What I did was to run a piece of 2x3 steel tubing from the left I beam to the right I beam, just about centered under the tank. What I am doing is simply tweeking the factory design a little bit. If everything is right in your rig, and you left it alone, you shouldnt need the brace. By plugging the overflow vents as the factory installed them, I am putting more water in the tank than they planned. What this does is allow me to fill the last couple of inches of the tank, above the vents. The brace just helps with the extra weight of the water.

There are a hundered little things the factory could do to upgrade their products. But as someone else here has said, if they did them all it would cost 20 grand more and be a Landmark, or whatever.

Much to my wifes dismay, I simply cant leave well enough alone. Its a curse.

TimK

 

[woodburner]

Tell me if I'm misunderstanding here....you folks are loosing fresh water in an area that is supposed to be insulated? What is happening to your insulation? This can't be right....I must be mis-reading this....