2018 Seneca crushed water tank

[Robbbyr]

Thanks for the update, good luck!

[ALJO]

When I installed the heating pad I installed the Tank on 1/2" Ply with 2x4 fir cross-members resting on the chassis channel, I didn't trust the 3 L brackets they install from the factory. Those tanks are very flexible for expansion. It will expand at least 15%.
Also did run the overflow lines 24" up and then down in a 2" ABC pipe.
Its my home (RV) and can do what it I want.

[Berjr]

Originally Posted by Robbbyr

I was at the factory service center last year and I spoke to them about a siphoning issue I had. They explained there are 3 vents since our Senecas, and many other Jayco models, can direct full city water pressure via the panel valves to the water tank when filling. Jayco wanted to make sure the tank does not overpressurize and rupture if the tank completely fills and the water supply is not stopped immediately. Hence 3 overflows. Other RVs with only a "gravity fill" for the freshwater tank don't generally have the same potential to overpressurize the tank.

But as stated in the earlier posts these same overflow tubes function as vents to allow air to enter the tank as you use water. If the tubes are blocked, when the pump is operated the tank will go negative (below atmospheric pressure) and collapse.

To that end, Jayco told me it is better to install an air break to stop siphoning versus blocking the overflow/vent lines. Less chance of trouble if the vents are not opened before filling or use of the tank. I built and installed my own air break and it has eliminated my siphoning issue.

Is it possible to see another view of your airgap ? where does it make the vacume break? We have the same issue with our 2018 Greyhawk and would like to give this a try before i try my other idea; which was to combine the vent lines and run them up inside the vanity and back down, and adding an auto vent to the high spot to break the siphon effect , Of course i would rather not add another hole in the floor to do this.

[Robbbyr]

Originally Posted by Berjr

Is it possible to see another view of your airgap ? where does it make the vacume break? We have the same issue with our 2018 Greyhawk and would like to give this a try before i try my other idea; which was to combine the vent lines and run them up inside the vanity and back down, and adding an auto vent to the high spot to break the siphon effect , Of course i would rather not add another hole in the floor to do this.

Here is the manifold I made, the air gap is created from the tank connection side being mounted lower than the overflow side. The tilt isn't very obvious in the picture below likely because of the camera angle.

Being a Seneca I had enough room between the tank and the compartment ceiling that it effectively breaks the siphon effect. Also because of the height difference, my hot water recirculation inlet drains back into the tank when activated. May not have enough room in another type of unit.

I used to leave a steady stream of water when driving, not anymore!

[WinnieView]

The solution we found 2 years ago was simple and works for ours. We have the same 3-4" gap above the fresh water tank.

[Berjr]

Awesome thank you , I just crawled under mine and it looks like i have about 1.5" maybe 2" above the tank. We don't have the recirculating line in our unit. Not sure i could reach the fittings on top of the tank but there is no reason i could not relocate one of the vent lines (or all) above the unit. I first thought there where 3 vents because the tank was compartmented , but i don't think this is the case they are much to close together like the picture 2008seneca just posted. If i can reroute a vent line or even 2 above the tank that might be all i need to do. Thank you

[Robbbyr]

Originally Posted by Berjr

We don't have the recirculating line in our unit.

No one does, a feature I added to save water when boondocking. Instead of running it down the drain waiting for it to get hot I just hit the button and wait 30 seconds. Hot water right there at taps then! Excess water directed back to freshwater tank.

[Berjr]

nice idea. Boondocking is all we do, no hookups at the races. Greyhawk is new to us, we wanted more room than our Hyperlite toy-hauler trailer. Now just to work out the bugs in the new unit. most of which is just a learning curve but losing 1/3 of a tank of water is the biggest. thank you