2021 37K - Water Tank

lawingnutz · 08-22-2021, 05:30 PM

Before i go climbing around under my Seneca, can someone please tell me tbe exact location of the fresh water storage tank on a 2021 37K coach?? I want to resolve the siphoning issue.

75462 · 08-22-2021, 07:59 PM

Quote:

Originally Posted by lawingnutz

Before i go climbing around under my Seneca, can someone please tell me tbe exact location of the fresh water storage tank on a 2021 37K coach?? I want to resolve the siphoning issue.

On my 2020 37K, it's above the propane tank. I removed the panel and can open my propane door and see me fresh water level. The best way to get to the tank vents is on the wet bay side. On mine I can crawl in.

Gunfighter · 08-22-2021, 08:28 PM

^^ Yes. Passenger side pull panel above the propane tank. My wetbay has a "full" panel going across rather than a 1/2 panel. We have a 2018.5 37K

Firewrench · 08-30-2021, 10:00 AM

2021 Accolade, same location. The tank just sits in there “loose”. A metal bracket on the left rear and a piece of styrofoam wedged in front are supposed to keep it from moving around.
Yesterday I went out to drain the tank and refill. There was chunks of soft dark brown gunk coming out the drain! Eeewww…
I’ve been sanitizing, last trip was a month ago. Not sure where we picked up the “infection”. After several drain and refills, not much better. Sure glad we can access the tank on the right side on these models. I cut a 2” hole in the side of the tank near the top so I could look inside. Used my pressure washer to clean the gross stuff from tank walls. Took the utility bay apart so I could crawl in there to look at the outlet and vents. The outlet is on the bottom, tank laying on outlet hose, almost pinched closed. There is a couple pieces of styrofoam underneath supposed to support the tank off of hose. Not working too well. I put some wood under the “inner” or left, edge and under the outer “right” side to hold up the tank better. After cleaning out, I made a 3x3 plate from aluminum to cover the hole, and screwed it on, using some silicone gasket maker. No real pressure in there.
I think my mistake was leaving the tank half full. After this I will keep tank full when not using the rig for more than a week, and keep bleach in the water.
The pieces of wood in photo were just temporary to get the water over to the oulet.

Grumpy · 08-30-2021, 10:59 AM

Quote:

Originally Posted by Firewrench

I’ve been sanitizing, last trip was a month ago. Not sure where we picked up the “infection”.

Some CG have non-chlorinated well water and after being to one we had water go sour too.

Firewrench · 08-30-2021, 11:41 AM

That was my thought.

Rustynuts · 08-30-2021, 12:53 PM

My 2018.5 RB is in the same location. I used a piece of wire to pull the vent lines up and over the top of the tank and then added a raised pvc pipe manifold above the tank level as a vacuum break. It has never siphoned since. I ended up just leaving the carpeted panel off so I can visually see my water tank level and I keep my propane hoses for the QD BBQ connection there too.

Also consider checking to see if you water tank needs added support under it to keep it from sagging. Many of us here have added bracing between the frame rails and the compartment the water tank is in to keep it from sagging when full.

Firewrench · 08-30-2021, 05:23 PM

Looks like your water tank is more centered, mine is clear over to the right side(nice weight distribution, Jayco! Maybe they figure it counterbalaces the big couch/dinette slide)
There are 2 supports for the propane tank, and the plastic floor of the tank space sits on those and the frame rail. There was some sag between those propane tank supports and the frame rail. I was able to slide a piece of 3/4” plywood under the water tank, it now spans that saggy spot.
As for the 3 vent hoses, they are at the left front of the tank, I already have the utility bay back together. I’m not going to worry too much about those right now. Except for the fact that they are almost right above my air dump solenoids. I’ll crawl under there and put some extensions on them for now to keep the water off those solenoids.
I’ve been watching the mirrors when the water tank is full, haven’t seen too much water on the ground when stopping or going down hills.

Firewrench · 08-30-2021, 05:31 PM

Here’s my “tank access/cleanout hatch”. I used stainless machine screws so that there are maximum threads per inch in the plastic.
I filled the tank, it doesn’t leak. Yay!

lawingnutz · 09-01-2021, 03:10 PM

Thanks for the help, but i’m a bit confused on how the PVC will act as a siphon/vaccumn breaker??… First what are the three vent lines for? When i overfill it water appears to come out of all three but only one continues to siphon the water down to the 66% level, which is about 2 inches from the top.

Explain how to connect the three vent lines to a PVC manifold…drawing would help…Thanks!!

Rustynuts · 09-01-2021, 07:17 PM

Quote:

Originally Posted by lawingnutz

Thanks for the help, but i’m a bit confused on how the PVC will act as a siphon/vaccumn breaker??… First what are the three vent lines for? When i overfill it water appears to come out of all three but only one continues to siphon the water down to the 66% level, which is about 2 inches from the top.

Explain how to connect the three vent lines to a PVC manifold…drawing would help…Thanks!!

Basically the PVC pipe is creating an air gap or chamber. When a siphon starts, it fills the vent lines up with water pressure and fills the tubes enough to fill them to the point below the water tank height. Once this starts you have to either stop the supply to the vent lines or insert air in the tubes to stop it. If you look at my pics, the first one shows on the right where the factory vent lines are connected to barbed fittings, then it angles up and the pipe runs along the floor and into manifold that new vent lines attach to. In order to start a siphon on what I built, you would have to fill the entire manifold under pressure for it to start but there is so much air space and an upward climb, it is much less likely to happen.

Robbbyr · 09-01-2021, 07:35 PM

Quote:

Originally Posted by lawingnutz

Thanks for the help, but i’m a bit confused on how the PVC will act as a siphon/vaccumn breaker??… First what are the three vent lines for? When i overfill it water appears to come out of all three but only one continues to siphon the water down to the 66% level, which is about 2 inches from the top.

Explain how to connect the three vent lines to a PVC manifold…drawing would help…Thanks!!

Here's mine. Disregard the hot water return fitting, I installed a hot water recirculation system and that is where it is returned to the tank instead of going down the drain until it gets hot.

The manifold is mounted in a "tipped" position; the connections to the tank are lower than the connections to the vent/overflow lines.

lawingnutz · 09-01-2021, 07:43 PM

What is purpose of 3 vent lines on the tank?? What not plug the one that siphons the water down to the 66% level?? Will the the other 2 provide enough overflow protection??

Robbbyr · 09-01-2021, 08:34 PM

Quote:

Originally Posted by lawingnutz

What is purpose of 3 vent lines on the tank?? What not plug the one that siphons the water down to the 66% level?? Will the the other 2 provide enough overflow protection??

I was told by Jayco Service the purpose of 3 overflows is to ensure the tank does not get over-pressurized and suffer a rupture since it is directly connected to outside water pressure when filling. If one blocks one or more overflows and you have high filling pressure it could damage the tank. I have almost 90 psi static pressure at my home, I even use my regulator when I fill even though I still have 3 always open overflow/vent lines. When it is full it squirts quite forcefully out those hoses at a set pressure of 50 psi. So I suspect I am pressurizing the tank some with all 3 flowing.

Before I did my air break manifold I sometimes was spewing water from all 3 overflows when I would start driving with a full tank. Now I don't lose any.

Rustynuts · 09-01-2021, 08:48 PM

Quote:

Originally Posted by lawingnutz

What is purpose of 3 vent lines on the tank?? What not plug the one that siphons the water down to the 66% level?? Will the the other 2 provide enough overflow protection??

I have had all 3 of my fitting out of the tank and all 3 just screw in flush with the inside of the tank, not one of them extends down into the tank at all. It may just be the mounting position of that hoses fitting which is causing that one to keep siphoning.

lawingnutz · 09-01-2021, 08:53 PM

So basically you are taking the 3 - 1.2” vent lines from the tank and connecting them together on an air chamber (2” pipe??) and then running 3-1/2” lines out of the air chamber…correct??

lawingnutz · 09-01-2021, 09:08 PM

Here is a picture of the 3 vent lines…they look equal..so why does the middle line siphon the water down to 66%, about 2”???

Rustynuts · 09-01-2021, 09:19 PM

Quote:

Originally Posted by lawingnutz

So basically you are taking the 3 - 1.2” vent lines from the tank and connecting them together on an air chamber (2” pipe??) and then running 3-1/2” lines out of the air chamber…correct??

Basically but one key point is having the new vent lines coming out of the chamber higher than the incoming lines.

Firewrench · 09-01-2021, 10:44 PM

I was able to look inside the tank thru my access hole last week, no downtubes or anything like that on the vents. Backed the rig up by the house today to load up for a little trip this weekend, it’s a pretty good hill, 200 feet long and gain about 30 feet. Tank was brim full, must have lost at least 10 gals. Guess I’ll be working on an air break system sooner rather than later. So I get to take the utility bay apart again…<sigh>
We’re heading south in about 3 weeks.
Thanks guys for the photos. Gives me a good plan.

Rustynuts · 09-01-2021, 11:02 PM

Quote:

Originally Posted by Firewrench

I was able to look inside the tank thru my access hole last week, no downtubes or anything like that on the vents. Backed the rig up by the house today to load up for a little trip this weekend, it’s a pretty good hill, 200 feet long and gain about 30 feet. Tank was brim full, must have lost at least 10 gals. Guess I’ll be working on an air break system sooner rather than later. So I get to take the utility bay apart again…<sigh>
We’re heading south in about 3 weeks.
Thanks guys for the photos. Gives me a good plan.

That how I discovered mine, our driveway is a downhill right turn. I had filled the water and then went to fuel up and when I came home that downhill right turn forced all the water pressure to the front corner where the vents are and I got out and heard the water pouring out all 3 vent tubes.

You may also like: