I hope this was the right move.

[boyscout]

So my understanding is that there is supposedly a 60 gallon fresh tank and then a 6 gallon water heater, that would give me a total of 66 gallons. This is how it works in my last two coaches as well. Just not as much water. When I do fill up I initially filled until I saw the light read full at which point there was 38 gallons of water in the tank. I then let it fill until water came out of the blue overflow tube and at that point I stopped it and it reads 44.5.

Did you move the trailer after filling your tank? If you filled to overflow you should have been close to advertised capacity, but then your fresh water supply would have been susceptible to a "siphoning" effect that has often been reported when the trailer is moved with a full tank. The water sloshing around in the tank gets into the overflow circuit which can then start sucking it out and dumping it on the road while you drive.

The fix for this is to buy a 3/4" (IIRC, double check first) Sharkbite valve and slip it onto the PEX overflow pipe sticking out the bottom of your trailer. Turn the valve off while towing your trailer with a full tank of water, but REALLY important to be sure that it's open at ALL other times.

[Onebadhawk]

My wife and I boondock quite a bit..
Not always, but not always a campground with hookups..
All of the tank capacities were of high importance when we chose our 297RSTS..
It had listed 93 or 96 on the fresh and 84 on the gray..
The first thing I found out ( shame on me for not catching this on the initial walkaround )
was the 84 gray was 2 -- 42 gal tanks..
One get the shower pan and the kitchen sink and the other gets the bathroom sink and the unused washer hook up from the bedroom closet..
Needless to say I can brush my teeth into a 42 gal tank for an awfully long time but the shower pan and kitchen sink are a consumer of gray space..
This certainly should have been the shower pan and the washer hookup together,
but I have found I can get them to self level by keeping the cap on the 3" outlet and opening both gray valves.. ( I hope this is ok )..
Well, after just a few runs we kept running low or out of fresh water..
I finally found its a 60 gal tank.. Not a 93 as advertised..
I questioned this,, I asked, there must be a way to get more fresh capacity, won't a bigger tank fit, or can I add another tank..
Absolutely not,, it won't work, it won't fit in the same place and there's no other place to put a tank..
This is what GD told me after consulting thier build schematic..

If your questioning exactly what equipment your rig was built with GD has a schematic of the build as it went..

Ohh,, I was told that specifications can change without notice..

Teddy

[Spettiner]

I put a shark bite valve on the overflow tube. It began to spill over way before the tank was full. The valve corrected the problem.

[macroman]

Can someone explain to me the purpose of the overflow tube? I think I am having the same problem of water being siphoned out and my fresh water capacity being compromised. After I fill up my fresh water tank I see water come out of the over flow tube for quite some time. I like the idea of the valve that "boyscout" and "Spettiner" suggest.

[FT4NOW]

Can someone explain to me the purpose of the overflow tube? I think I am having the same problem of water being siphoned out and my fresh water capacity being compromised. After I fill up my fresh water tank I see water come out of the over flow tube for quite some time. I like the idea of the valve that "boyscout" and "Spettiner" suggest.

One purpose is an overflow so you dont pressurize the tank when filling. The other purpose is a vent so it let's air in the tank when using the pump and prevents drawing a vacuum on the tank.

Sent from my SM-G950U using Tapatalk

[MaryNTony]

One purpose is an overflow so you dont pressurize the tank when filling. The other purpose is a vent so it let's air in the tank when using the pump and prevents drawing a vacuum on the tank.

Sent from my SM-G950U using Tapatalk

Does anyone know if the fresh water tank is vented other than the overflow?

[Onebadhawk]

I have the same problem..
I stop filling when water starts coming out of the overflow..
I check the gauges and it would say 100%..
It would come out of the overflow for quite a bit..
Then I'd pull away from the house..
I'd run out of water way too soon..
So I made a habit of checking the gauge after the fill at the house and as soon as I got to my destination..
When I got where I was going The gauge would say 50%..
The only conclusion I could come to was the overflow tube was siphoning the tank..
I put PVC on the overflow and ran it so it's easily accessible at the side of the rig and put a valve on it..
Now when I'm done filling and the gauge says 100% I close that overflow valve..
Then when I get to my destination the gauge still says 100% and I open the valve so I don't create a vacuum in the tank..

I don't know if there's another vent in that tank..
I kinda wouldn't think so though..

Teddy