24MBH fresh water tank ?

[tjcj]

Just bought our 2017 24MBH ( first tt ) last weekend and prepping it for its maiden trip next weekend. Question is do I fill it all the way up or stop a couple gallons shy of full ? Wondering if it will splash all over if filled full.
Thanks Allen

[themickeyd]

We have only run one trip out of the water tank, and filled all the way up before leaving. Once we got to the campground (120 mile hwy drive) we found the water had sloshed around enough that we had about 1/4 missing. It didn't leak inside but I think we lost out the vent tubes. There is a bit on the forum about siphon loss of water from the tanks, that may have been some of the problem, but I'm not convinced that is what did it.

[Nukeneck]

Unless you're going somewhere where there's no water, I would tow it empty. Most CG's (on the west coast) allow you to pull up to a provided water spigot and fill your fresh water tank. Why tow the added weight unless you're boondocking

[blderman]

Originally Posted by tjcj

Just bought our 2017 24MBH ( first tt ) last weekend and prepping it for its maiden trip next weekend. Question is do I fill it all the way up or stop a couple gallons shy of full ? Wondering if it will splash all over if filled full.
Thanks Allen

The tanks on my 23mbh siphon a lot no matter what level I fill them to. I put caps on the overfill hoses but the water still leaks past them so I am going to install valves instead. I primarily boondock and will not risk not being able to find water in route so I always fill the tanks all the way.

From my Note 5

[tjcj]

Nukeneck I will primarily be boondocking with the trailer.
Blderman where does the water siphon to ? This is our first tt so we know nothing about them or the "quirks"

[dewey02]

This is a common problem for Jayco and Starcraft FW tanks.
Search on "Fresh water pukes" to see a description of the problem, several pages of responses by non-believers, and then several suggestion for fixing the problem by those who have experienced it first hand (including me).

The fix works. The water empties out of the overflow tubes and you can easily lose 1/3 to 1/2 of your tank in this manner, depending upon the length, bumpiness and curves in your drive.

[blderman]

Originally Posted by tjcj

Nukeneck I will primarily be boondocking with the trailer.
Blderman where does the water siphon to ? This is our first tt so we know nothing about them or the "quirks"

It siphons out of the overflow tubes. The other trailers I owned did not have these tubes so I am not sure why Jayco thinks it's necessary.



From my Note 5

[tjcj]

Ok so it looks like I have to plug the overfill tubes while traveling. Where should I look for the overflow tubes ?

[dewey02]

If your FW tanks are located right over your axles (many are) then the overflow tubes will likely be just behind your TT wheels. I have two small white tubes hanging down. I just connected them together and added a shutoff.

Remember to be sure to keep the shutoff OPEN while filling the tanks, as the overflow tubes also act as a vent and allow air to escape as water is going in.

Also remember that once you get to your campsite and set up you need to re-open the shutoff so that air can get back into your FW tanks as you draw water from them. This is especially important if you have twin FW tanks that are tied together.

Only time the shutoff on the overflow tubes should be in the closed position is after you are done filling and while you are travelling.

[dewey02]

Originally Posted by blderman

It siphons out of the overflow tubes. The other trailers I owned did not have these tubes so I am not sure why Jayco thinks it's necessary.
From my Note 5

With your elite model, I believe you have a 2nd FW tank for greater FW capacity. The vents are needed because of the way the two FW tanks are tied together to equalize the water level between the two. The gravity fill goes just into the first tank. That tank can expel some air via the gravity fill or vent that ties to the gravity fill. If you fill too fast, you will get burping as the air tries to escape via the same route that the water is going in.

But the second tank only gets filled by a 1.5 or 2 inch hose that connects to the first tank and equalizes the water levels between the two. Once the first tank gets a couple inches of water in it, that equalization hose is completely under water and there is no way for the air in the second tank to escape. So the overflow tubes also act as a vent for the second tank, letting the air escape so the water can enter via the equalization tube. Same thing happens when you turn on your pump and draw water out of the tanks. Without the overflow/vent tube on the second tank, you will be creating a vacuum if air can't get back into the tank.

That's why it is important if you put a shut off on the tubes to always have it open when filling and when drawing water out.

[blderman]

Originally Posted by dewey02

With your elite model, I believe you have a 2nd FW tank for greater FW capacity. The vents are needed because of the way the two FW tanks are tied together to equalize the water level between the two. The gravity fill goes just into the first tank. That tank can expel some air via the gravity fill or vent that ties to the gravity fill. If you fill too fast, you will get burping as the air tries to escape via the same route that the water is going in.

But the second tank only gets filled by a 1.5 or 2 inch hose that connects to the first tank and equalizes the water levels between the two. Once the first tank gets a couple inches of water in it, that equalization hose is completely under water and there is no way for the air in the second tank to escape. So the overflow tubes also act as a vent for the second tank, letting the air escape so the water can enter via the equalization tube. Same thing happens when you turn on your pump and draw water out of the tanks. Without the overflow/vent tube on the second tank, you will be creating a vacuum if air can't get back into the tank.

That's why it is important if you put a shut off on the tubes to always have it open when filling and when drawing water out.

Thanks dewey02, I guess I should have clarified that I understand the mechanical aspect of why Jayco did this, I don't understand the way they routed the hoses. Had they been ran vertically into a wall cavity and terminated with an exterior, screened vent, the siphoning action would be a non issue. That is how my other trailers were done. I think Jayco took the easy route with this design and it's a poor one at that.

From my Note 5

[dewey02]

blderman: I agree with you about the poor design. It has been a known problem for years and no sign that they are even attempting to address this issue.