Water tank siphoning or purging while traveling

[powerscol]

Can someone from the factory please comment on this.

OK - took a short trip today (about 10 miles) to weight the unit and get tires balanced. To get a good weight I had the water tank FULL when I left the house and both gray tanks 1/3 full from my sanitizing, etc. After my short trip to town and back I discovered my water tank was now 1/2 full. I could see it dribbling as I made turns and a lot dribbled out on the scale. So I have no choice but to put a valve on the tank overflow tube, I plan to make a label and added it to the KantLeak/Nautilus box to remind me to open it while filling and camped, but if I leave the KantLeak/Nautilus on power fill the street check valve should open under vacuum while traveling - correct? And If I leave a faucet open would that relieve pressure when changing elevation? Hopefully someone from the factory know something.

BTW I also found out both gray valves leak - good thing I bought those end cap valves folks recommended.

[powerscol]

I posted my solution here
https://www.mygrandrv.com/fo...ution?p=172541

[Second Chance]

I believe that overflow tube also serves as the vent when you are filling the tank. Make sure it's open as you fill or you may pressurize your fresh tank.

Rob

[powerscol]

I believe that overflow tube also serves as the vent when you are filling the tank. Make sure it's open as you fill or you may pressurize your fresh tank.

Rob

Rob - you are very correct. That's why I printed out the labels to remind myself when filling or dry camping.

[Jerryr]

I believe that overflow tube also serves as the vent when you are filling the tank. Make sure it's open as you fill or you may pressurize your fresh tank.

Rob

Rob,

Also make sure it’s open when using the water from the tank to prevent it from collapsing.

Jerry

[powerscol]

Rob,

Also make sure it’s open when using the water from the tank to prevent it from collapsing.

Jerry

Correct. That's the reason I brought it forward to where I could reach it easily. It should also be opened when draining the fresh water tank.

[offtohavasu]

The other issue (not trying to bash on you) is altitude changes with the expansion and contraction of the air. The more air in the tank, the more it's going to happen. Take a look at a water bottle when the lid is sealed tight as you go up and down in altitude. Same thing happens to the tank if it's sealed off.

[powerscol]

As the dealer will need to drop the belly wrap to fix the leaking gray tank valves I plan to try and install what is called an air/vack valve (has a float to prevent water escaping but lets air in and out) above the tank T'eed in with the drain relocation. The air/vack will solve the operational issues while the drain valve will stop the draining while traveling. This is something GD should consider.

Thoughts

My new system did work for my short trip

[offtohavasu]

You don't want to prevent any water from coming out because you don't want to blow the tank when it gets full.

[powerscol]

Correct - that is why it will be on a T in the line and be placed at the high point. The lower pipe will still be to the vent drain valve, and when that valve is closed the air/vac will handle and issues on use and change in altitude. The trick will be to get it above the tank top. Ill know more when the belly is off. Its hard to enplane without a picture.