LAVAC a different approach

[HermanD]

I have a Lavac toilet and want to change the outlet to a holding tank. To get permanent rid off the smell off the seawater, I want to change, to use fresh water from drinkingwater tank no:2 (180ltr.).
Is it possible to minimise freshwater use, by not using the vacuum principle, but after delivering your sewage to the bowl, pumping little fresh water in the bowl, with a footpump and then pump out with the Henderson MKV to the holding tank??
It is just one idea. If the lid is closed and use vacuum, you cannot see when the sewage is pumped out off the bowl. Only by experience you discover you need XXX strokes on the pump and perhaps use more fresh water then needed.
Experience? Opinions?

 

[Peggie Hall HeadMistress]

Welcome aboard!

Glad to see that you're now able to post! To repeat my reply to your PM this morning...

Connecting ANY toilet designed to use sea water to the potable water system is a BIG no-no...and every toilet mfr specifically warns against it because it cannot be done without risk of contaminating the fresh water system with e-coli, damage to the toilet, or both. However, there is another way:

Most intake odors are a result of sea water stagnating in the head intake and pump while the boat sits. Pouring water into the bowl doesn't solve the problem because water in the bowl only goes out the discharge, it doesn't rinse out the intake. So....

Reroute the head intake line to tee it into the head sink drain line just ahead of the thru-hull (this has the added benefit of eliminating one hole in the boat or freeing it up for other use)...the toilet will have no problem pulling in sea water. When closing up the boat (or any time you need to flush out the system), after you've closed the sea cocks, fill the sink with clean fresh water...flush the toilet. Because the thru-hull is closed, the toilet will pull the water out of the sink, rinsing the sea water out of the ENTIRE system. Adding some white vinegar to the sink water will also help to prevent sea water mineral buildup in the system.

There's been a lot of discussion in the HM forum about doing this...spend some time browsing and reading. And if you still don't find the answers you need, I'm always glad to help.

Btw...reading your profile, you list your location as ZH. My brain isn't coming up with a country to match those initials...where is "ZH?"

 

[Ed A]

peggy,
it seems to me the t fitting would allow air to come down the sink easier than lifting the water. you would just suck air?

maybe if the t was at the thru hull.. humm interesting idea here.
thanks

 

[Peggie Hall HeadMistress]

Maybe the solution is TOO simple...

'Cuz I'm amazed at how many people ask this question!

it seems to me the t fitting would allow air to come down the sink easier than lifting the water. you would just suck air?

Not if you put a plug in the sink to flush the toilet! If you've lost the plug for your sink, you can buy one at any hardware store for $1 or less.

Although...if you tee into the drain line below the waterline, that may not be necessary.

 

[JMM]

'Cuz I'm amazed at how many people ask this question!



Not if you put a plug in the sink to flush the toilet! If you've lost the plug for your sink, you can buy one at any hardware store for $1 or less.

Although...if you tee into the drain line below the waterline, that may not be necessary.

I just did this this summer when re doing both our heads this summer. Peggy is correct, the stopper mosty works very well and works much better on the sink that has the tee a little lower below the water line. You do need a good fitting stopper. Ours are rather old and sometimes bounce back up with the pump stroke.

 

[HermanD]

Explanation Zh

Peggie,

When I signed in this group the computer forced me to fill the county.
I did ZH this is one abbrevation off ZuidHolland (SouthHolland).
In that part off the Netherlands if live.

I understand the concern off connencting the inflow off a toilet to
the fresh water supply for contaminating, but every home toilet
is also connected to the fresh water supply. (Well be us in the Netherlands
without any problem).
The toilet itself (a LAVAC is only a bowl with inlet and outlet) will have
no problem with the fresh water. And the Henderson V sucks everything.
I do not know if fresh water in the holding tank, works better then salt
seawater?

I want only this constuction for: No smell, mimium water use, so it takes
longer before the holding tank has to be emptyed. And I never have to open
the underwater ballvalve inlet wenn I come on board and close wenn I leave the boat.

So this a different approach for the LAVAC.

Herman.

 

[Rick D]

Re: Explanation Zh

Herman, I don't think Fisher is still in business, are they? They were good boats. I'm surprised someone didn't buy them up.

 

[HermanD]

Rick,
The Fisher motorsailer is still build by Northshore UK, but because most off the production is handwork it is only possible to buy by miljonairs.
So mine is 32 years old. I am the 3th owner off this wunderfull motorsailer.
Herman

 

[Peggie Hall HeadMistress]

Herman...the difference between marine toilet and household.

You said (correctly), ", but every home toilet is also connected to the fresh water supply..."

The water for a home toilet is connected to a tank that supplies the bowl by simply dumping its water...so there's no way that bacteria in the bowl can have any contact with the fresh water supply. Additionally, the water supply on land is ALWAYS pressurized.

But there is no buffering tank between the fresh water plumbing and a marine toilet... In fact, you noted (also correctly) that the LAVAC is only a bowl with inlet and outlet...the fresh water plumbing would be connected directly to the bowl....AND--the water is only under pressure when the water pump is on. So there's nothing to prevent bacteria--notably e-coli--from migrating into the potable water supply.

There are marine toilets designed to use onboard pressurized fresh water, but the Lavac is not one of them...nor is any MANUAL toilet. So if you're determined to use fresh water to flush, you have two choices:

1. install another water tank to supply flush water to the toilet. It must be totally separate from your fresh water system...NO common plumbing--not the fill, not even the tank vent.

2. Choose an electric macerating toilet designed to use pressurized fresh water. Among European brands, Tecma is one...SaniMarin is another, both as that brand name and also as private label brand names by Vetus and Dometic.

 

[Stu Jackson]

http://c34.org/bbs/index.php/topic,5755.msg38216.html#msg38216

And welcome to the Forum.

 

[HermanD]

Peggie your description off a home storage tank brought me on
one idea.
Fresh water pumped in a kind off bottle, that has direct flow on the
underside off the bottle to LAVAC inlet. With overflow on 2/3 height
off the bottle. And for extra safety one check-valve in the fresh water inlet.
The overflow drains in the (bilge) sump. Bottle mounted high enough
that under sail the bottle is always above toiletlevel. So no dirty water
can go in the fresh watertank. See PDF drawing.
It is just again one idea. I have already removed the toilet seawaterinlet
and closed the hole in the hull. So I want to flow the toilet only with fresh water.
I should be using watertank no:2 as mentioned in the 1 post. Watertank 1 (under
the cabin sole = 160 ltr) is used for drinking water. Tank no:2 is selden used for
drinking water. I make no ocean trips.
Whell what about this?

I have have heard no comment on the question, if NOT using the vaccuum
priciple, but only pumping with the lid open, wil this work to empty the bowl.

Herman

 

[dhays]

Sounds to me like you should just replace the Lavac. The Lavac head is a great head for many reasons. However, what you are describing doing would take some of the advantages of the head and turn them into disadvantages.

Buy a new head and then feed it from that second fresh water tank. However, never EVER consider that tank to be a potable water source again and use it just for flushing the head.

 

[Peggie Hall HeadMistress]

It's the seat and lid that make the Lavac a Lavac...remove those and you have a porcelain toilet bowl like any other. Feed water to it, use any pump to pull contents out of the bowl and push them on on their way.

However, if you're gonna do that there's no need to spend the money for a Lavac. Just buy any toilet bowl and base, a Whale or Henderson diaphragm pump and hoses...you've got it all.

Btw...nothing I've said should provide you with any ideas to connect your toilet to ANY tank or plumbing that has ANY connection to the fresh water system. Feeding a "bottle" from it is a bad idea. It's not JUST the flush water tank that makes it safe to connect a 'home' toilet to the potable water plumbing...water to your home is ALWAYS pressurized. Onboard water systems are only pressurized when the water pump is on.

However, you're obviously determined to connect a toilet to the fresh water system that is not designed to be connected to the fresh water system. I've done all I can to talk out of doing that, but it's your boat and your health and the health of your crew, not mine. Good luck!