Reply
 
Thread Tools Display Modes
Old 03-03-2010, 09:22 AM   #1
Senior Member
 
Lawfive's Avatar
 
Join Date: Feb 2010
Location: Lafayette, CA
Posts: 157
Question Water Supply Siphon

I read the earlier posts a while ago about water siphoning out of the fresh tank during a fill. The solution was to close the air vent with an added valve of some kind when the siphoning started. Okay, then leave the valve closed while traveling. Doesn't that stop any water flow inside the coach? When reaching destination and opening up the valve, doesn't the siphon process start up immediately?

My 391 has a "corrugated" pipe as the water vent. It's sort of a 1 1/4" version of a sewer line. Searching around online I finally found a barbed fitting that should work on the end and allows a valve of some sort to be screwed into the end. Before I take off on this task, I would love to get some input from smarter folks who've already solved my problem. "Steal ideas from the best, with pride" is my motto.
__________________

__________________
Lawfive is offline   Reply With Quote
Old 03-03-2010, 11:46 AM   #2
Senior Member
 
NWJeeper's Avatar
 
Join Date: Aug 2008
Location: Enumclaw, WA
Posts: 2,617
Quote:
Originally Posted by Lawfive View Post
I read the earlier posts a while ago about water siphoning out of the fresh tank during a fill. The solution was to close the air vent with an added valve of some kind when the siphoning started. Okay, then leave the valve closed while traveling. Doesn't that stop any water flow inside the coach? When reaching destination and opening up the valve, doesn't the siphon process start up immediately?

My 391 has a "corrugated" pipe as the water vent. It's sort of a 1 1/4" version of a sewer line. Searching around online I finally found a barbed fitting that should work on the end and allows a valve of some sort to be screwed into the end. Before I take off on this task, I would love to get some input from smarter folks who've already solved my problem. "Steal ideas from the best, with pride" is my motto.
If you find where your tank is (mine is above the propane tank) you will notice access disks that can be removed to "access" the water pump area and the vent. I have removed one of these disks and just left it out. I then pulled my vent hose up out of the hole it was in and stuck it out the access port. That way the hose is more or less level with the top of the tank. I have also put a peal and stick zip tie anchor on the ceiling of the tank compartment and zip tied the vent hose up so that it runs higher than the tank for the most part. If you remove this entire panel then you have easy access to the pump and hoses in there. You could replace that corugated hose with a vinyl hose like the early '09 and earlier rigs had and that is easier to put a valve on too.

You are correct, simply adding the valve at the end of the vent doesn't completely stop the siphoning when you open the valve after a day of driving unless you blow into it or something to stop the siphoning action.

If the vent is closed, your pump will still pull water but it will collapse the tank. If this happens, fill the tank the next time with the valve closed and it will pop back out.

I will try and snap some pics of it and post them later.
__________________

__________________
"I can fix it, and if I can't fix it, I can fix it so no one can fix it!"
Ed & Wendy
2009 Georgetown 378TS | 1998 Jeep Wrangler | 1998 Skeeter ZX202C
Nights camped in 2009: 53 | Nights camped in 2010: 55
www.nwjeepn.com
NWJeeper is offline   Reply With Quote
Old 03-03-2010, 12:05 PM   #3
Moderator Emeritus
 
Join Date: Nov 2008
Location: Winston-Salem, NC
Posts: 2,381
I have read the post on the vent line siphoning problems, and while I don't have a coach, or that problem, I'm left wondering what is really going on. In order for the vent to siphon, the water level would have to be above and forced out of the vent. Then once the overflow is full, the water supply turned off, the siphon would start. As long as air was allowed in the tank, the siphon would continue until the water level fell below the vent, at which time air would be pulled in to the siphon hose, and the siphoning would stop. If no air was allowed in to the tank, the siphoning process would stop when a vacuum had been pulled on the tank itself. The location of the vent in regards to the tank, would determine the water level left in the tank after the siphoning has stopped. The vent has to be fairly high if not at the top, or you would force water out while trying to fill the tank.

Solution: If you can get to the vent hose inside the coach, find the vent line. Make sure it is higher than the tank. At the highest point of the vent line, install a "tee" and add an extra piece of hose running up the wall. This will act as a vacuum breaker, and prevent siphoning. Being a "vent" line, this will never see pressure and no water should ever climb up and out of this hose. The worst case would be foul smelling water, and maybe being able to smell that near this other vent line. This can be minimized by reducing the inside vent line to a very small opening. This will cure the siphoning problem, and no valves to buy or remember.

I may be wrong, just applying plain on physics here and how a siphon works. Someone correct me, and I'll take no offense.
__________________
LadyWindrider
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic

2008 Work and Play 18LT
LadyWindrider is offline   Reply With Quote
Old 03-03-2010, 12:08 PM   #4
Senior Member
 
ronhanson's Avatar
 
Join Date: Jun 2009
Location: Colorado
Posts: 322
The pump will pull sufficient vacuum to let you use water in the coach while traveling. You wont even notice a change in the flow rate. You may not want to do this for very long since you may damage the tank if it holds a vacuum, but I've actually forgotten to open my valve after arriving at the campsite and didn't remember until the next morning. Much water had been consumed with no ill effects.

When at the site, the tank isn't sloshing around enough to start the siphoning. Providing you didn't overfill the tank to a point it's pressurized and you hadn't consumed any water it's normally not a problem.

I would very much like to see inside the tank as to how the vent is configured. It's amazing how much water it can siphon out.
__________________
Ron Hanson
2009 Georgetown 350TS (bunks)
400W solar, 440AH 6V GC2
2009 Ford Edge AWD Ltd towed
2011 Honda Fit Sport towed
ronhanson is offline   Reply With Quote
Old 03-03-2010, 12:13 PM   #5
Senior Member
 
ronhanson's Avatar
 
Join Date: Jun 2009
Location: Colorado
Posts: 322
Quote:
Originally Posted by windrider View Post
I have read the post on the vent line siphoning problems, and while I don't have a coach, or that problem, I'm left wondering what is really going on. In order for the vent to siphon, the water level would have to be above and forced out of the vent. Then once the overflow is full, the water supply turned off, the siphon would start. As long as air was allowed in the tank, the siphon would continue until the water level fell below the vent, at which time air would be pulled in to the siphon hose, and the siphoning would stop. If no air was allowed in to the tank, the siphoning process would stop when a vacuum had been pulled on the tank itself. The location of the vent in regards to the tank, would determine the water level left in the tank after the siphoning has stopped. The vent has to be fairly high if not at the top, or you would force water out while trying to fill the tank.

Solution: If you can get to the vent hose inside the coach, find the vent line. Make sure it is higher than the tank. At the highest point of the vent line, install a "tee" and add an extra piece of hose running up the wall. This will act as a vacuum breaker, and prevent siphoning. Being a "vent" line, this will never see pressure and no water should ever climb up and out of this hose. The worst case would be foul smelling water, and maybe being able to smell that near this other vent line. This can be minimized by reducing the inside vent line to a very small opening. This will cure the siphoning problem, and no valves to buy or remember.

I may be wrong, just applying plain on physics here and how a siphon works. Someone correct me, and I'll take no offense.

You are correct. I don't know how the vent is configured but I've seen it suck a tank 1/2 empty so the inlet reaches pretty far inside. It should only be at the top of the tank.

The problem with trying to raise the vent level or add any additional piping is the lack of room in the compartment. The tank goes right to the top of the basement.
__________________
Ron Hanson
2009 Georgetown 350TS (bunks)
400W solar, 440AH 6V GC2
2009 Ford Edge AWD Ltd towed
2011 Honda Fit Sport towed
ronhanson is offline   Reply With Quote
Old 03-03-2010, 12:21 PM   #6
Moderator Emeritus
 
Join Date: Nov 2008
Location: Winston-Salem, NC
Posts: 2,381
If you can get a "tee" in the vent line, and a piece of hose high enough to prevent sloshing out the added hose, you'll break the vacuum and the siphoning will stop. The new hose can even point down and go out the same vent hole, you just need it to break the vacuum of the siphon. Then it really won't matter where the vacuum line is in the tank.
__________________
LadyWindrider
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic

2008 Work and Play 18LT
LadyWindrider is offline   Reply With Quote
Old 03-03-2010, 12:23 PM   #7
CLASS "A" Senior Member
 
cfsoistman's Avatar
 
Join Date: Nov 2008
Location: Upperco, Maryland
Posts: 3,135
Quote:
Originally Posted by ronhanson View Post
The pump will pull sufficient vacuum to let you use water in the coach while traveling. You wont even notice a change in the flow rate. You may not want to do this for very long since you may damage the tank if it holds a vacuum, but I've actually forgotten to open my valve after arriving at the campsite and didn't remember until the next morning. Much water had been consumed with no ill effects.

When at the site, the tank isn't sloshing around enough to start the siphoning. Providing you didn't overfill the tank to a point it's pressurized and you hadn't consumed any water it's normally not a problem.

I would very much like to see inside the tank as to how the vent is configured. It's amazing how much water it can siphon out.
You nailed it! The problem occurs from the sloshing during travel not at any other time. I didn't have a problem for 2 years but last September the road, if you want to call it that, was a far from smooth,level or anything close and we rock n rolled our way in. It was there I check the tank that was 2/3 full when we left but now about 1/3 full. Water drops were present on the screen of the vent so I knew it had recently happened. Since I installed the valve - no water lost - open the valve once I set up and barely a tablespoon or two. Bought one 3/4 PVC Valve, it fits snug into the pool type hose they used. I cut a small piece off and inserted the valve and placed the small piece with the screen on the open end. Used a little bit of white electrical tape, which I already had and it looks fine. My problem solved!
__________________

2007 Georgetown 370TS
aka - RAYNMKR

Driver: Charlie
Navigator: Sheri
cfsoistman is online now   Reply With Quote
Old 03-03-2010, 12:32 PM   #8
Senior Member
 
ronhanson's Avatar
 
Join Date: Jun 2009
Location: Colorado
Posts: 322
Quote:
Originally Posted by windrider View Post
If you can get a "tee" in the vent line, and a piece of hose high enough to prevent sloshing out the added hose, you'll break the vacuum and the siphoning will stop. The new hose can even point down and go out the same vent hole, you just need it to break the vacuum of the siphon. Then it really won't matter where the vacuum line is in the tank.
It's a great idea, but on mine you simply cant raise the level of the intake point for a vacuum breaker or the vent hose opening high enough to prevent water from coming out while traveling. You'd get a wet basement. There is a slide above the tank so you cant even go into the house with any plumbing. The valve is a simple solution providing you can remember to open it. Once it's part of your setup 'routine' it's not that big of a deal.
__________________
Ron Hanson
2009 Georgetown 350TS (bunks)
400W solar, 440AH 6V GC2
2009 Ford Edge AWD Ltd towed
2011 Honda Fit Sport towed
ronhanson is offline   Reply With Quote
Old 03-03-2010, 01:08 PM   #9
Senior Member
 
flyrotor's Avatar
 
Join Date: Sep 2009
Posts: 755
Just wondering, considering windrider's suggestion, and listening to the comments about space limitations.

Using the tee as mentioned, would you be able to install a short nipple capped with an anti-siphon valve as used in the sprinkler system industry? The intent of the anti-siphon valve is to prevent water leaking under pressure, and allow it to drain when not under pressure. This potentially could "break" the closed system which causes a siphon, but prevent water from leaking out when sloshing. This might be a good subsitute for the hand valve which could sometimes be forgotten. Goes along with windriders setup, but may well fit into the space limited compartment and prevent soaking everywhere.

Just a theory, would it work? My trailer doesn't siphon, but I have seen it squirt out when making right turns.
__________________
flyrotor is offline   Reply With Quote
Old 03-03-2010, 01:40 PM   #10
Senior Member
 
NWJeeper's Avatar
 
Join Date: Aug 2008
Location: Enumclaw, WA
Posts: 2,617
Quote:
Originally Posted by windrider View Post
In order for the vent to siphon, the water level would have to be above and forced out of the vent. Then once the overflow is full, the water supply turned off, the siphon would start.
One of the big problems with our coaches that is different than a lot of others is that our tanks are the full width of the rig but only about 4 or 5" high. It only takes just a tiny bit off level to the passenger side to get the siphon going. Most other coaches have tanks that are 12 to 18" high and when vented properly there is no way for them to siphon.

Charlie hit it right on the head that while traveling that short tank combined with the rocking of the rig means you can loose 2/3s of your water over a day of traveling. From the top of the tank to the top of the compartment it is in is only mere inches so I don't know if there is enough room for a "T" in there but I like the idea.
__________________

__________________
"I can fix it, and if I can't fix it, I can fix it so no one can fix it!"
Ed & Wendy
2009 Georgetown 378TS | 1998 Jeep Wrangler | 1998 Skeeter ZX202C
Nights camped in 2009: 53 | Nights camped in 2010: 55
www.nwjeepn.com
NWJeeper is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 08:21 AM.