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E-34 Water System Vacuum Problem

razehnder

RAZehnder
I have a problem with the freshwater system on our 1987 E-34 that we bought 2 years ago. I'm hoping that someone may have heard about or run into and solved the problem.
Our E-34 has three solid polypro water tanks. One is forward under the v-berth, the second is under the starboard cabin seat, and the third is under the port settee seat immediately in front of the galley counter/icebox. The vent lines from each tank run along the bottom of the hull and merge under the galley counter/sink. A single merged vent line runs up to a spigot in the sink which I believe is standard.
The problem is that when filling the tanks water invariably enters and fills the vent line(s). The result is that when water is pumped from any one of the tanks a vacuum is created in the tank due to water in the vent line(s) blocking the air flow that would equalize the pressure or lack thereof.
Initially we get reduced flow from the spigot but I think we actually ruined a freshwater pump before we discovered the problem. I'm thinking we could actually collapse a tank if the pump didn't fail first.
The way I've combatted the problem so far is to open the on-deck fill cap slightly to allow air into whatever tank we are using when at anchor. There is always a surge of air entering the tank as I loosen/remove the fill cap if we had been pumping water. We generally try to avoid pumping much water while underway. But this is not a good long-term solution. I asked the former owner about it and he said he never noticed a problem. But he also said he had never used or filled the forward tank and apparently seldom used much water on the boat.
There is a short tail-end hose coming off the merged vent lines under the galley counter with a plug on the end. I've tried draining the vent lines with that tail but it's difficult/impossible to the drain enough water to resolve the problem. The drained water also runs in to the bilge which is not preferable. I figured I might be able to use that tail to pump the water out of the vent line(s) but it would be a lot of trouble to go through every time we filled the tank(s). It would also reduce the total amount of water we could store for longer cruises in remote areas with limited access to potable water.
I've thought of somehow attaching/inserting a small vacuum release valve to each tank that would allow air in but no water out if that is possible or if they even exist. I've tried to do a little research on that but have come up empty so far.

Has anyone heard of or encountered this problem and resolved it? I'm open to solutions.

Sorry about being long-winded.
 

Rhynie

Member III
Raz,
It is a long shot, but around here we have problems with mud daublers plugging up vent holes. Just this afternoon I removed the transom vent (like thru hull with two little screens) one screen was missing and the inside was plugged with mud. My telltale was water blowing back out of the deck fill spout when I removed the hose.
Make sure your vent is venting.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
I know that Ericson liked to put those chrome-brass spigots on the counter for the vent line for each water tank, and on our boat they put such a vent in the aft head for the second tank aft and of course there was one at the galley counter for the settee tank. Both tanks were rotomolded plastic from Ronco Tanks.
I admit to being surprised that they combined three vent lines into one...
However, if it worked when new and not in the here and now....
There must be something that has changed...
:confused:
I would first get at each tube connection and take it apart and blow thru it and make sure each is clear. I once had to use my Zodiac pump (!) to blow thru one of the plumbing lines on our boat while doing some trouble shooting.
:)
The thing is, that if you have some standing water in a vent line for the tank you are pumping from, the pump will instantly suck that standing water right back into the tank. I would guess that there is something a lot more solid than mere water in one of the lines, especially the merged one to the counter spigot. I would back-pressure that one first and see if it is clear.
When we run the system pressure pump on our boat I can put a finger tip over the counter spigot and feel the vacuum immediately.

Let us know how your trouble shooting progresses. Like I said, if it worked in 1987, it should still work in 2009. ;)

Cheers,
Loren
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Note: the pump is pulling water out of the tank. Without a vent the tank would collapse or the pump would stall. That is the purpose of the vent letting air in to displace the water being removed.
When you fill the tank there is room around the hose nozzle and much air being displaced will come out there, and some, of course, will exit thru the vent as the tank is filled.
There should never be pressure or vacuum in the tank itself.

Loren
 

Chris A.

Member III
I have a 34 with the same setup you describe- there is a stopcock on the end of the tail you are talking about instead of a plug. I do get water in the vent lines but air seems to get through it as I have not had trouble filling or emptying the water tanks. The vent spigot in the sink spits quite a bit of water and air when filling the tanks.

I too am wondering if there could be an obstruction somewhere in your vent lines making them less effective? Do you try leaving the plug off of the tail for awhile? This would at least make a lower drainage point to get some of the trapped water out of the vent lines.

I never really liked the spiderweb of vent lines for these tanks for this reason of accumulating water.

Good luck with it,


P.S.- oops others posted while I was writing this--- sorry if redundant
 
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Tom Metzger

Sustaining Partner
Damn tank vents

The vent design on the E-34 is probably the the single worst design on the boat as far as normal operation goes. The tanks are located where it is not easy to put a proper vent. Leading the tank vents down from the tanks below the sole and then back up again guarantees that they will fill with water, and snaking them under the sole and through the grid makes visual inspection impossible without destroying the sole.

On my boat there is no problem pumping water out of the tanks, but I have a problem filling them. The lack of a vent causes the water to leak past the inspection port seal on the starboard tank if I over fill it. Ericson recognized this and put a sheet in the Owner's Manual saying to fill the tanks gently. This caused a problem with the adjacent cabin sole, a problem that has been corrected. I live with the filling inconvenience.

The port tank is OK with the vent at the galley sink if separated from the other vents and routed to avoid the dip. I suppose that the starboard tank could be vented to the head sink, but that is a tough run to make and may not be doable. The V berth tank puts too much weight in the bow so I don't use it, but it would be possible, I think, to vent it into a V berth hanging locker and down into the bilge.

If I couldn't pump water out of a tank I would suspect a crimp in the vent line. I would try blowing through the line to be sure it is wide open. A crimp may have existed since the boat was built.
 

footrope

Contributing Partner
Blogs Author
Your description is very similar to my experience and you already know it's due to water in the vent lines. Just water -- that can't escape. I was dealing with a long run of vent line from my forward settee tank to the vent spigot at the galley sink. The line was half full of water and it had low spots. Not sure why some similar installations worked just fine.

The link below is from an old thread. It was an interesting project and the last post is what I ended up doing. You may not be able to do this, or you might be able to figure out a variation that will work for your particular tank/filler arrangement. This method has worked fine for 4 years. No mud daubers go there, no need to periodically clear the vents with a pump or compressed air, no cracking of filler caps. It's hidden in the forward hanging locker, where the filler hose happens to be.

My V-berth tank vents quite adequately to the head sink. A short run from a tall tank - our head is forward.

I have just about gotten all the old, sticky, fuzz-covered vinyl hose out of the boat and that settee vent run was the longest. The leftover hole at the galley sink is sporting a handy sprayer these days.

http://www.ericsonyachts.org/infoexchange/showthread.php?t=1909&highlight=vented
 
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razehnder

RAZehnder
Thanks for the help. It sounds like I'm not the only one to experience problems with water tank venting. Just to be clear...the vent lines on our E-34 are free of any kinking or obstructions. Air/water pours out of the vent spigot at the galley sink whenever we fill the tanks.I agree with Tom Metzger above. The water tank venting system is very poor on the E-34. A proper tank vent extends upward from the tank, preferably to a point higher than the on-deck fill port. This is very difficult on the E-34.
The first indication of the problem occurred when I heard a tiny air leak when it was very quiet down below. The sound only occurred after we pumped some water. I was able to determine that the leak was coming from a point just below the on-deck fill port for the forward tank. I believe that the leak is due to air leaking into the tank/hose through a tiny hole in the fill hose line. It may be where the ends of the wire bracket that is attached to the fill cap chain protrude through the walls of the fill hose. The sound eventually stops when the pressure equalizes but it can take a long time. The only way to quickly stop the sound is to remove the fill cap and allow air to rush into the tank.

Keep any suggestions coming.
 

kevin81

Member II
Your description of the vent lines is different than on my 1989 E-34. Maybe the factory knew of the problem and changed the design in the following years. Or, one of the previous owners had the same problem and changed the vent lines and added individual vents.

My port tank vents to the galley sink, the starboard tank vents to the head sink (aft head), and the optional forward tank vents to the anchor chain locker. After reading your post last night, I checked the routing of the vent hoses for each tank and all appear to not have any "traps" (for holding water) and all routed to be above the top of the tank.

I have never had a problem with a vacuum in the tank.

Sorry I couldn't think of any easy fix.

Kevin
1989 E34
 

footrope

Contributing Partner
Blogs Author
Just to clarify my solution - I plumbed the new settee tank vent, via that vented loop, to the v-berth tank filler hose. When I fill the settee tank I keep an eye on it, but any overflow will go to the forward tank, and the loop closes so that the water stays in water lines. I did several tests to make sure I could fill in either order and let it overflow, without adding water to the hanging locker.

It may work to vent a tank to it's own filler hose using the loop, but filling to overflowing could result in submerging the vent and having to run the water out before capping the filler, but that isn't much of an imposition. In fact, you may find that you can draw enough to make the vent effective, before the vacuum is too great for your pump.

There are several good ways to fix this and you are absolutely right about the desirability of getting the vent above the top of the tank filler. Mine doesn't quite achieve that goal, but comes close enough. Getting a vent above deck level is going to be tough. I think the weight of trapped water in these long vent hose runs is overcoming the ability of the pumps to suck it back into the tank. Good luck!
 

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razehnder

RAZehnder
kevin81--
You say "the optional forward tank vents to the anchor chain locker."

I've actually considered doing that very thing. But since my forward tank is in the aft storage locker under the V-berth I would have to drill through at least three locker walls to be able to extend a vent line forward into the chain locker and end it at a high point under the deck to one side of the anchor locker. The nice thing about that would be that the end of the vent line might be above the fill opening. I suppose I could live with that but am interested how that is done on your boat. I'm not sure there is another option in extending a line forward to the chain locker.

How does the vent line run forward on your boat?


footrope--
You've given me some ideas also. Thank you. Picture helps immeasurably.
 
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kevin81

Member II
Next weekend, I'll take some pictures of the forward tank's vent and post them. I won't be able to go to the boat this week but will be there next weekend.

Kevin
1989 E34
 

razehnder

RAZehnder
No rush Kevin. I don't want you to go through a lot of trouble but if you were able to post a picture or two it would be greatly appreciated.
 

Shadowfax

Member III
I have a '88 E34. On this boat the plumbing exists for the addition of a water tank in the vee berth, however it was never installed. I never looked into installing one as I felt that that much weight in the bow was not necessarily a good thing. With all this talk of vee berth water tanks I'm curious. What is this tank made of? Is it a hard tank or flexible? How much water does it hold. Do you really use it because of the additional weight and trim issues?
 

razehnder

RAZehnder
Shadowfax-
The v-berth tank on our E-34 is a rigid tank, I believe made of polyethylene. I believe I misspoke on the orig. post when I said it was polypro. I think the tank was factory installed when the boat was originally purchased. I believe the owners manual lists the tank as holding 25 gallons but we filled it last year with measured buckets of water and it only held about 23-24 gallons. The tank is located in the most aft center storage locker under the v-berth. It is secured in place by wooden brackets so it wouldn't move even upon capsizing.
I'm slightly concerned about the added weight in the bow but it doesn't seem to dramatically impact the performance or seaworthiness of the boat. The bow may sit an inch or two lower in the water when the tank is full but otherwise the impact is not particularly noticeable. In smaller waves or chop of say less than a couple feet it seems the added weight may actually help the bow drive through and toss aside the waves. We've only owned the boat for 2 years and have yet to sail in larger waves. We also seldom race the boat and use it almost entirely for cruising.
We generally don't use the tank for shorter weekend type cruises (2-3 days) because we don't need the extra water. But for longer cruises we usually fill the tank because we sometimes are in remote areas of B.C. where we may go a week or more without access to potable water. We tend to avoid resorts if possible. The additional water capacity is definitely appreciated in those circumstances. We generally use the v-berth tank first so that we limit the amount of time the weight is in the bow even if it doesn't seem to present any significant problems.
 

Chris A.

Member III
What he said

Paul,

I agree with the previous post. I keep the forward tank empty except for cruising where the extra capacity is appreciated. I don't seem to notice any practical trim / handling issues under cruising conditions but always use the forward tank first. (I have a leak in that tank now, and am thinking the storage room in that locker might be nice without a water tank in there- but I'll probably repair / replace the tank anyhow)
 

kevin81

Member II
Here are some pictures of the forward tank and vent. As you can see, the vent hose is connected to the top of the tank, then routed to the starboard side of the compartment. The vent hose runs forward, then to a vent in the anchor locker.
As I noted in an earlier post, I don't know if the tank was factory installed or added by a previous owner. In the picture you'll notice a 2x4 on the top of the tank. It is fastened to the compartment. I think the purpose is to secure the tank.

Kevin
1989 E34
 

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razehnder

RAZehnder
Thanks Kevin. This is very helpful and I appreciate your efforts.
The routing is basically what I was envisioning but a picture is truly worth a thousand words. One concern I might have is ending the vent line into the side of the anchor locker where it would be exposed to seawater or other contamination. It might be a good idea to point the end down and attach it to the anchor locker wall to help prevent this. Some form of fine mesh screening on the end might also help prevent spiders and such from entering the water system.
I was also wondering if it is possible to end the vent line inside the chain locker (unused on our boat) by attaching the end as high as possible under the deck on the fore side of the forward wall of the v-berth. Hope that makes sense. I don't recall how much room there is inside the chain locker to accomplish that but I will take a look inside the chain locker door next time I'm at the boat. I think I've only looked in there one time when we first bought the boat.

Thanks again Kevin. "You da man" as they say.
 

kevin81

Member II
A follow up - the picture doesn't show it clearly but there is a vent with a screen. The vent is mounted on the side of the locker, near the top. (Attached is a picture of the same type that is installed.) I have never had a problem with the locker filling with water and backfilling the tank. I'm not saying it couldn't happen but I'm not too worried.

Kevin
1989 E34
 

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u079721

Contributing Partner
That vent fitting is the same one that the factory used for the other external vents, so that might be an original installation of the vent for the forward tank.

But I would always worry about water backing up in the anchor pan and getting into the fresh water system. We did not have the forward tank in our boat, but we did sometimes have the anchor pan drain get clogged with mud and have the pan fill up with water when it rained.

Since we're just talking about fresh water here, why not have the vent mounted in the forward area underneath the anchor pan? When you fill the tanks the overflow would admittedly go into the bilge, but the rest of the time the vent would be protected from spiders and external water. Any reason why that wouldn't work?
 
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