311 holding tank question and fresh water prime question

[Catsail]

Hello, I am a new owner of a 1999 Beneteau 311. I have two questions please:

1. The head has two discharge lines via a Y valve - one goes to the top of the holding tank and the other to the discharge seacock. No macerator observed. The holding tank has a pump out and vent at the top, but also a discharge line exiting the bottom that runs to the discharge seacock. A Y fitting connects the two discharge lines - one from the head and the other the holding tank, to the discharge seacock. No valve s are are involved. So it seems to me, this unit was designed to empty the holding tank overboard as well as to pump waste directly overboard. Is this correct? I guess the waste seacock must be closed at all times or else the holding tank will empty. I wish there was a valve to close the holding tank discharge so that the head could be used to discharge immediately bypassing the holding tank. As it is setup, the holding tank would empty when this option was selected I think.

2. Having trouble priming the fresh water pump. I cleaned the screen filter before attempting. Should all faucets be open when trying to prime? Suction is being created on the supply side as evidenced by a sucking sound when I remove the filter. Perhaps the supply side just needs to be open to release air. Any priming suggestions?

Thanks, Jerry

 

[DougM]

The Y valve is between the head and the holding tank. It works like railroad switch. Position 1 pumps head waste to the holding tank. Position two pumps it over the side.
For the most part the valve should be locked out so that waste cannot mistakenly be pumped overboard.
What goes into the holding tank stays there until its pumped out from the deck fitting.

 

[Peggie Hall HeadMistress]

1. The head has two discharge lines via a Y valve - one goes to the top of the holding tank and the other to the discharge seacock. No macerator observed.

No macerator pump is needed in the line from the toilet.

The holding tank has a pump out and vent at the top, but also a discharge line exiting the bottom that runs to the discharge seacock. A Y fitting connects the two discharge lines - one from the head and the other the holding tank, to the discharge seacock. No valve s are are involved. So it seems to me, this unit was designed to empty the holding tank overboard as well as to pump waste directly overboard. Is this correct?

That appears to be the case. The second discharge line IN the bottom--not AT the bottom--of the tank and the absence of any overboard discharge pump seems to indicate that the tank is entirely above the waterline, allowing it to drain via gravity. If any part of the tank is below waterline, it would fill with sea water to the waterline instead of draining when the seacock is open--which it would have to be to flush the toilet directly overboard.

I wish there was a valve to close the holding tank discharge so that the head could be used to discharge immediately bypassing the holding tank. As it is setup, the holding tank would empty when this option was selected I think.

That's correct...opening the thru-hull to flush directly overboard would also dump the tank. But it shouldn't be a problem because it's illegal to flush the toilet directly overboard OR dump the tank except when in open ocean at least 3 miles from the nearest point on the whole US coastline...requiring that the seacock be kept closed and all waste go into the tank in all waters inside the "3 mile limit."

 

[Gunni]

Doesn’t make sense. Why would there be a y-valve combo from the pump out top fitting AND the tank bottom fitting to the overboard discharge? Back in 1999 these installations were typically done by the dealer’s yard monkeys. Believe you need a re-working of the install done by a competent pro.

 

[Peggie Hall HeadMistress]

It's definitely different, but it actually does make sense, Gunni...but ONLY if the tank is entirely above the waterline, allowing it to be dumped via gravity instead of using a pump. That requires a discharge fitting IN the bottom of the tank--which is where he seems to indicate that it is. It's usually done using a y-valve in that discharge line with a line to the deck pumpout fitting. Whoever installed this system opted for a separate pumpout fitting in the top of the tank with with a diptube inside to the bottom, eliminating the need for that y-valve. The y-valve in the toilet discharge line provides a choice of flushing directly overboard or into the tank.

 

[Philip_Oceanis 361]

Have a look at the attached. You have the holding tank with one seacock/throughull. The other one with two is an option.

 

[Catsail]

Thanks everyone for sharing you thoughts. Peggie is correct, the holding tank is well above the waterline.

With the head y-valve in the holding tank position, waste is pumped to a fitting at the top of the holding tank into the tank. Two other fittings are on top - a pump-out and vent.

On the bottom of the holding tank is a fitting with sanitation hose the runs to a y fitting, not a valve, just a simple 2 hoses into 1 connector. The other side of the y fitting is sanitation hose from the y-valve near the head that gives you the holding tank/overboard option. The y brings both to the discharge seacock. There is no locking mechanism on the seacock. I am able to nylon wire tie the y-valve in the holding tank position.

I may see if I can install a valve in the discharge hose at the bottom of the tank. It seems to me that black water will fill the hose to the seacock othewise. And I put conditioner in the holding tank that I don't think would be good to just discharge into the ocean (over 3 miles out).

 

[Catsail]

Have a look at the attached. You have the holding tank with one seacock/throughull. The other one with two is an option.

Thanks Phillip, mine is definitely the one throughull method. I like the idea of fewer seacocks, but I don't like the idea of wastewater sitting in the discharge hose of the holding tank. I am going to research a valve that I can install just below the holding tank to stop waster water from entering the hose and just sitting there - right to the discharge seacock.

 

[Gunni]

Beneteaus put the tank discharge on the bottom to allow them to be plumbed for gravity discharge if apprpropriate. Plumbing the head discharge to the tank top is also common. Yes, you need to valve off the tank bottom discharge line so that section of hose to the thru-hull does not sit full of black water when using the holding tank. You will permeate your hose and odors will propagate.

 

[Peggie Hall HeadMistress]

Yes, you need to valve off the tank bottom discharge line so that section of hose to the thru-hull does not sit full of black water when using the holding tank. You will permeate your hose and odors will propagate.

Another reason to install a shutoff valve in the tank discharge line: It's likely to fill up with sludge if the tank isn't rinsed out several times a season. It's not hard to do...just put about 6" of water into the tank via the deck pumpout fitting--'cuz that sends the water into the tank at the bottom to stir up any sludge and hold it in suspension...dump the water. Repeat a couple of times. You won't be able to do this at a pumpout 'cuz you'll have to open the thru-hull each time you dump. If you have a washdown pump--sea water or fresh--you can use it to supply the rinse water.
Ideally the shutoff valve should be installed directly into the discharge fitting on the bottom of the tank...but keeping in mind that it needs to be conveniently accessible, that may not be possible...it may have be a foot or more from the tank. That makes it even more important to rinse out the tank fairly often 'cuz the sludge will fill up a short section of hose really quickly.

And I put conditioner in the holding tank that I don't think would be good to just discharge into the ocean (over 3 miles out).

Sounds like you're using a toxic chemical tank product. Switch to bio-friendly product--Raritan K.O. is a live bacteria product....No-Flex Digester is a blend of bio-friendly chemicals...the active ingredient in Odorlos is nitrates. All do an excellent job of preventing odor while breaking down and emulsifying waste and TP.

You might also consider checking out the link in my signature...it's a comprehensive "marine toilets and holding tanks" manual that will help you learn to prevent 99% of problems instead of having to cure 'em.

 

[stevemitchell]

Thanks for this post and discussion. I have a 2000 311 with the exact same configuration, and have had some problems with odors, which I've posted about before. I replaced my manual, constantly failing head with a wonderful electric Raritan, and at that time, replaced all of the hoses up to the Y-valve which dramatically reduced the odors.

However, I wanted to update the rest of the piping in the next month to non-porous pipes as well as correct the same setup that is listed above. All this info helps with my planning!

 

[Peggie Hall HeadMistress]

If your hoses have a route that's a lot of "over, under, around and through," your best--and easiest to install--hose/piping choice is Raritan SaniFlex hose. It's a bit pricy (best price I've found is $11/ft for 1.5"), but has proven to be 100% odor-permeation proof and is so flexible it can be bent like a hairpin without kinking. RaritanSaniFlex hose

 

[Catsail]

If your hoses have a route that's a lot of "over, under, around and through," your best--and easiest to install--hose/piping choice is Raritan SaniFlex hose. It's a bit pricy (best price I've found is $11/ft for 1.5"), but has proven to be 100% odor-permeation proof and is so flexible it can be bent like a hairpin without kinking. RaritanSaniFlex hose

Great information Peggie - thank you.

Jerry