Hoses off of fresh water tank

DSK360 · 05-29-2019, 03:09 PM

Hey guys. I have an octane 161. Most of my camping is at race track so I have no access to water. Which means I fill the tank before I leave. Same thing we've done in my old man's dune seeker for as long as I can remember. But when I get to the track with the 161 I've lost about 1/3 of my fresh water. I know there are two hoses that stick down under the sheeting that water runs out of when the tank is full. I had assumed this was how the tank was vented. But I checked and it also vents next to the fill tube. So since it is vented up high what is the purpose of the low tubes and is there any harm in plugging them?

dewey02 · 05-29-2019, 05:05 PM

You can put valves on those, but I wouldn't plug them permanently.
They DO serve as both overflow and vents. You will need to have them open when you fill (so air in the tanks can vent out). And when you camp and use water from your onboard tank (so air can get back in).

Sometimes when there are the overflow tubes, the factory workers don't even connect the vent tubes. And with some models, there are dual FW tanks and the vent only services one tank.

**JFlightRisk** · 05-29-2019, 06:20 PM

Dewey02 is correct, and this is what I did to stop the siphoning. I open them when filling, and then again when using the pump.
You can see my valve set up in my albums.

DSK360 · 05-29-2019, 06:51 PM

Wouldn't the air in the tank vent out of the small white hose next to the fill tube as the tank filled up? As well as come in when the water is being drawn out? I don't think I have 2 tanks since my capacity is 54 gallons. I was worried about the vent not being hooked up but it appears it is.

DSK360 · 05-29-2019, 06:54 PM

Quote:

Originally Posted by JFlightRisk

Dewey02 is correct, and this is what I did to stop the siphoning. I open them when filling, and then again when using the pump.
You can see my valve set up in my albums.

What kind of valves are those that you used?

Brownie · 05-30-2019, 06:23 AM

Losing about 1/3 of your water is normal. The sloshing of the water during travel tends to set up a siphoning action that doesn't stop until the water level in the tanks drops below the overflow tubes. I put a barbed hose fitting and a hose clamp on both of mine, then screwed a 1/4-turn shutoff valves on each (like what you'd put on the water lines under your sinks). I open them while filling; close them (for travel) when water comes out of them; then reopen them after my first shower or after washing dishes (to allow air into the tank). It's worked for me for six years, now.

I cut off about 1/2" of the hose and took it with me to Home Depot to make sure I got the right size barbed x threaded hose fitting and matched the threaded side to the threads on the shutoff valve.

Hope this option does the trick for you!

**norty1** · 05-30-2019, 07:26 AM

There are threads on JOF that describe a fix which involves routing the overflow hose such that it's not in a position to continuing siphoning off water once it overflows.

Personally valves would be my last choice due to my KISS theory,

Keep it simple SIR!

dewey02 · 05-30-2019, 10:02 AM

Quote:

Originally Posted by DSK360

What kind of valves are those that you used?

I have dual tanks. I connected both overflows together and then just added a common Camco spigot.

**JFlightRisk** · 05-30-2019, 09:50 PM

Quote:

Originally Posted by DSK360

What kind of valves are those that you used?

I think the brand is Quest. It's been a few years since I did the install, and the valves were in my stash of "spare things I may need sometime in my life", or as the DW calls it, "stuff".
They are 1//4 turn valves, and probably available at any good hardware, or plumbing store.
I had to install two, as there's two 40 gallon fresh water tanks under there, each with its own overflow tube.

**JFlightRisk** · 05-30-2019, 10:04 PM

Quote:

Originally Posted by norty1

There are threads on JOF that describe a fix which involves routing the overflow hose such that it's not in a position to continuing siphoning off water once it overflows.

Personally valves would be my last choice due to my KISS theory,

Keep it simple SIR!

Norty, I agree 100%. But I was REALLY bored that day, and needed to do something. Actually, the DW told me to get out of her way, and go DO something....somewhere else!
This was a couple of days after seeing water spraying out from under a 5'er that passed us at about 75 mph on the interstate. At first, I thought he was overheating. It was the first time I've seen it happen first hand. They had to be losing a couple of gallons per mile.

(I thought KISS was keep it simple sometimes??)

TonyCO · 06-02-2019, 01:13 PM

Timely post DSK. This was our first big trip with the new trailer over Memorial Day. Moab, Durango, and the Great Sand Dunes. I filled up at the house because we just picked a spot on BLM in Moab for our first few days. We have two, 40gal. tanks and I noticed water coming out of the overflow lines during the drive. We lost about 1/2 the tank which surprised me. I was guessing I would just put two valves on as well, but I emailed Jayco and they told me to take it to the dealer and let them add to the overflow lines inside the tanks so it wouldn’t siphon anymore. I also noticed the siphon effect when we had less than 1/3 tank. The siphon continued even with that small amount of water in the tank. Is it smarter to let them add to the lines or should I just do the valves myself?

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