Fresh water tank issue

[dbahn]

Originally Posted by Bullitt6283

Okay, here's the deal...

If you're gonna block off those overflows to prevent water loss while traveling, you gotta remember to unblock them

• when you're filling the tank
• when you're drawing water out of the tank.

If you're afraid you might not remember to do these things, then you gotta install some valves to perform these functions automatically.


1. A pressure relief valve to prevent over-pressuring the tank
2. A vacuum relief valve to prevent pulling a vacuum on the tank.


These devices exist, just gotta find them. I'm working on it.
.

This simple and cheap homemade extension attached to one of the tubes does those things, and I just plug the other two tubes with rubber stoppers. The stoppers are a "pressure relief valve" that works by just blowing out the stopper if you over pressurize. The check valve lets air in to the tank in response to a vacuum in the system. I carry a few rubber stoppers in case I forget to remove one during fills.


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[dbahn]

UPDATE:

So in the process of sanitizing the system today I tested the check valve concept by filling the fresh water tank to overflowing, plugging the extended vent tube, connecting a tube with a air-filled bag tape to the open end and attaching that to the inlet of the check valve then inserting the rubber stopper. Basically that arrangement duplicates the situation where you forget to remove the stopper and force the check valve to respond the the tank vacuum.

Sure enough, with the tube plugged on the Normal setting as water was pumped out of the tank the air in the bag got sucked into the tank via the check valve. There was a bit of a lag at first (probably because there was SOME air in the tank) but then it seemed to draw an amount of air equal to the amount of water coming from the outside shower. Once the air was sucked out of the bag I removed the stopper and continued pumping normally.




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[8thdwarf]

Just got back from a trip around middle America that started from the west coast, AWSOME trip ... since the rig only has 10K on it, I'm taking to the dealer for warranty repair. #2 issue is the potable water tank issue.. #1 issue is the 120V breaker panel got really hot deforming the plastic box and damaging the buss bar and the 120V A/C breaker..... glad I was in the coach and noticed the smell. Other wise, had I been on a hike I would have come back to ashes.... we'll see how the dealership addressed these issues.

[16WhiteColly]

Check and tighten all the wires in the breaker panel. Probably find a bunch loose. Check occasionally.

[8thdwarf]

NO loose wires this time..... cked ALL connections... current draw was 11.3A on a 20A breaker.... burned buss bar and melted at that location... had to be a bad Breaker-Buss Bar connection....

we'll see how warranty handles it....

[Ricmasten]

Same problem on my Entegra Odyssey 25R. My solution, and it's working, was to put a double elbow at the end of each of the three hoses. I then added enough hose to the end of the elbow to run each hose back up to a level higher than the tank, which happens to be on top. I've heard it burp once on filling, but no water loss.

[dbahn]

That should work fine, but where do you run the hoses?

[Ricmasten]

I ran the hoses first down, as they are originally positioned, then with the elbows I reversed the direction to up and ran them to the top of the tank. The hoses all now have their ends lying on top of the tank and tied with zip ties such that they will not fall out. No pinched hoses and I believe, not putting too much pressure on the system while I'm filling the tank. I would mention that while I driven four different motorhomes over 500,000 miles and have done a lot of work on them myself, I am still only qualified as a "shade tree mechanic." Be that as it may, I do hope that my solution works as well for you as it has for me. The idea is to stop the siphon effect which occurs with the tank as it is. Before, I filled the tank to full, only to find it at 1/4 when we arrived ready to dry camp. Now it stays full, or at least it has since I made the change over 5,000 miles ago.

[MrSaxy]

Can anyone confirm that these two shut off valves and the two open ended lines shown on this picture of the left rear of our 21QB are the fresh water drains and the vents for the fresh water tanks?

[drmike961]

Originally Posted by Ricmasten

I ran the hoses first down, as they are originally positioned, then with the elbows I reversed the direction to up and ran them to the top of the tank. The hoses all now have their ends lying on top of the tank and tied with zip ties such that they will not fall out. No pinched hoses and I believe, not putting too much pressure on the system while I'm filling the tank. I would mention that while I driven four different motorhomes over 500,000 miles and have done a lot of work on them myself, I am still only qualified as a "shade tree mechanic." Be that as it may, I do hope that my solution works as well for you as it has for me. The idea is to stop the siphon effect which occurs with the tank as it is. Before, I filled the tank to full, only to find it at 1/4 when we arrived ready to dry camp. Now it stays full, or at least it has since I made the change over 5,000 miles ago.

This sounds simple and you say that it works so I am on board. Right now I have valves on the ends on mine but I'm tired of leaving myself notes and playing games with the valves on and off. In addition they are right next to the exhaust on my genny so laying on the dirt trying not to get burned has lost its luster.

[JFlightRisk]

Originally Posted by MrSaxy

Can anyone confirm that these two shut off valves and the two open ended lines shown on this picture of the left rear of our 21QB are the fresh water drains and the vents for the fresh water tanks?

It looks like your TT has the second fresh water tank option, so the two plastic turn valves should be the tank drains, and the other two tubes will be the low point drains. The T-handle pull-up valves for those will be inside, directly above them.