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Old 04-06-2011, 15:52   #1
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Lavac Head - Frequent Pump Rebuilds

It has been three years since we launched Namo equipped with two Lavac heads. There was a problem initially with lids (possibly due to outsourcing to Taiwan) that was fixed with the right glue however there is an ongoing problem with premature failure of the Henderson pumps. I have rebuilt three to date and am looking are doing it a fourth time and these are lightly used units. The problem is compounded by the excellent reputation of Lavacs so the builder installed the pumps in such away that an unpleasant afternoon is needed to access and repair them (remove toilet, bulkhead, etc.).

The symptom is that waste water in the hose above the pump seeps back through the pump and fills up the bowl. This is both off-putting and means that one can’t keep the bowl dry which is a problem in bumpy weather.

I seems that the valves scale up so I have tried flushing the units periodically with a dilute vinegar solution. When that didn’t work, I have also tried to de-scale them with dilute muratic acid but this seemed to reduce the strength of the pump’s valve material to that of a grape skin.

Has anyone else had this problem?
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Old 04-06-2011, 16:09   #2
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Re: Lavac Head - Frequent Pump Rebuilds

I have had a Lavac for nearly 9 years, and only once had to replace a seal. That was because someone dropped a solid object down the bowl, and flushed. I came along later, and without knowing what happened. I tried to force the object by pumping, blown seal. Sounds like something is wrong with the installlation, factory, or not.........i2f
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Old 04-06-2011, 16:16   #3
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Re: Lavac Head - Frequent Pump Rebuilds

First thing, are you using the original Taylors/blakes/lavac pump, as we had one on our boat for many years (living on board) and never needed to service the pump.

Secondly if your getting some fluid back through the pump, just lift the lid on the pan and pump a few times, they pump air as well as fluid, this will empty the pipe above the pump and should stop any reverse flow.
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Old 04-06-2011, 17:12   #4
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Re: Lavac Head - Frequent Pump Rebuilds

Thanks for your suggestions. Yes these are the white Blakes/Lavac/Taylor pumps supplied by Brendan's Isle in Florida and the rebuild kits have been made by Henderson of Belfast. The pump cases are sturdy and the diaphragms have been in excellent condition when I have done the rebuilds. The valves however are, as the English say, "perished".

I have tried pumping air into the lines but that does not seem to help, in fact, the valves seal better if they are pulled shut by the vacuum in the bowl. Pumping them dry with the lid open seems to result in a less complete seal in the pump.

I wonder if we see the problem because the pumps pump uphill to holding tanks under the deck. Probably eight to ten foot hose runs with four feet of vertical head pressure. In a more traditional arrangement, the hose runs would be shorter and would head down hill to a seacock.
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Old 04-06-2011, 17:33   #5
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Pumping s#!^ uphill...

I have the same problem using my KIS installation.

I installed a large holding tank above the waterline so there is a longish run from the pump to the top of the holding tank. When the bowl is emptied some of the "fluid" seeps back through the pump and into the bowl.

Having had to "disassemble" part of my system (now I know a 1" outlet - thanks PO - is too small...) you have my deepest sympathy.

My solution has been to 1) Add small amounts of bleach to my bowl water. This removes most of the scale and seems to help. and 2) If I'm in a situation where the backflow is likely to be a problem then I dry bowl, flush with clean water and pump enough through to fill the outlet pipe. The backflow leaves just enough water in the bowl for the next crew member...
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Old 04-06-2011, 17:51   #6
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Re: Lavac Head - Frequent Pump Rebuilds

I have had my Lavac for two years and had one valve fail. Interestingly, the rebuild kit came with a flap valve that "seemed" to have placed in the rubber frame from the factory. In fact, it was attached in reverse. The problem was back flow and very weak sealing pressure. I went around and around with the folks at St. Brendans Isle. He had know idea and wasn't until I was able to dig up the original and compare them together that I noticed the difference. The pump has worked like a charm since, approximately a hear and half ago. It's pretty to break the vacuum seal until the pressure dissipaites Probably, different than what you are experiencing since my backflow was significant and with a weak vacuum seal. Just a FYI, I suppose to Lavac owners.
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Old 04-06-2011, 17:52   #7
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Re: Lavac Head - Frequent Pump Rebuilds

I still haven't figured out how to remove this darn gas mask. I took apart that pump no less than a dozen times in a two week period.
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Old 04-06-2011, 18:35   #8
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Re: Lavac Head - Frequent Pump Rebuilds

Our Levac is 14 years old, on the original seal, and never a problem. Our pump has been rebuilt twice over that time, and the second time it was because we put vinegar in the pump and let it sit over night. BIG mistake, it shriveled the rubber flappers! Now we only let it sit for a few minutes when we use vinegar.

It sounds like you have problems with your installation, and/or a LOT of calcification in your area. We never had a problem with calcification in the pump. Flush water slowly running backward through the pump is normal, as it is just crude flapper valves. You need to have the pump high enough in the plumbing that it only has about a foot of hose above it, before it loops downward. We have ours on a 45 degree angle to accomplish this. This way the amount that can run backwards over time is limited. ALSO, be sure you flush enough that the contents of that foot of hose is just water!

Another point. The incoming H2O hose has a vent hole in the top of it's loop. (There are actually two available). This has to be the right one, and kept clear of salt clogs. We occasionally put some fresh water on the hole while it sucks air, to dissolve the salt.

The vacuum release vent can be made slightly larger by putting a pin in the hole to stretch it, then remove... It needs to be just large enough that you can lift the lid after a good flush, in about 30-45 seconds. If it takes longer, this makes the pump "back flow" problem worse.

I had heard that there was a fairly recent problem with lid gaskets, but before that cropped up, ALL of my boatbuilder/multihull friends installed Levacs. We ALL consider it the best made for simplicity and reliability. A normal pump rebuild interval should be at LEAST 5 if not 7 years! Like I said, I suspect your installation.

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Old 04-06-2011, 20:10   #9
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Re: Lavac Head - Frequent Pump Rebuilds

Hmm, well if as Mark Johnson advises that "Flush water slowly running backward through the pump is normal, as it is just crude flapper valves." is correct then I wish Lavac mentioned this in their literature.

In fact in their manual, Lavac says the opposite "With the Lavac system it is practical to install a high [holding] tank". The specs for the pump advertise a maximum head of fifteen feet.

Lavac also recommend "A useful approach to remove scale build-up is to introduce a solution of vinegar into the pump (by putting it into the bowl and with the lid open operate the pump for a fewstrokes). Leave for 24 hours and then flush thoroughly with cleanwater." But our valves looked shriveled as well when I rebuilt the pumps so perhaps this procedure is a culprit.


The head compartments on Namo are welded aluminum and the pumps are behind bulkheads so moving the pumps higher in the system is not a practical option.
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Old 15-06-2011, 08:16   #10
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Re: Lavac Head - Frequent Pump Rebuilds

Hi folks
Can anyone help with a similar question please? I installed the Henderson Mk5 hand pump that came with my Lavac Zenith about 2 years ago. It all works but I've always felt the pump doesn't have a smooth action, I have to jerk the handle rather than smoothly pull and release almost like there is some kind of packing bolt impeding it's travel. Has anyone else had this issue?

Also, I expected it to easily pump out my very small holding tank which is a few feet away and less than a foot to the deck outlet. It doesn't quite push far enough and I need the help of a separate electric pump to extract. Pumping sea water to the heads is fine.

I'm kind of expecting someone to say, 'you Wally didn't you remove the transport bolt before installing it?'

Any help/advice appreciated.
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Old 15-06-2011, 08:48   #11
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Re: Lavac Head - Frequent Pump Rebuilds

We had our Lavac for going on three years. Only had the pump jam once, and that was because some stuff was flushed that shouldn't have been. The hoses got completely full of deposits and the idea of redoing all those lines every few years is just completely gross to me. If you're living aboard full time, need a holding tank equipped, and are flushing with sea water, I don't see how you're going to get around needing to replace your hoses.

We have a composting head now. I would never go back to a wet system again. Our boat smells better, we have much more room, two less holes underwater, no worries about discharging overboard, and reduced maintenance.

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Old 12-07-2013, 11:13   #12
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Re: Lavac Head - Frequent Pump Rebuilds

As I am yet again rebuilding the Henderson pumps for the Lavac heads, I posted the following comment on Practical Sailor's website next to their Aug 2011 review of vacuum toilets:

We ordered two Lavac Popular models installed on our new sailboat in 2008 and it has not been an altogether happy experience.

The first problem was that the toilet seat seals did not seal perfectly and with air leaking in, there was little vacuum produced and little flushing. This was apparently due to the outsourcing of manufacturing to Taiwan and some quality control issues. We solved it by using the recommended glue and the manufacturer has corrected the fabrication process so should be nothing to worry about now.

The second problem, which continues, is seep back through the Henderson MK5 pumps into the bowls. In our boat the holding tanks are installed above the water line so that they can be drained when offshore by gravity alone. The nitrile joker valves in the pumps are quite flimsy compared to ones specially built for heads (e.g. Jabsco, Groco) and after a few months of use, they fail to keep the fluid in the hose from trickling back into the bowl. The valves when examined have lost their shape and are encrusted with salt deposits. Although nitrile is supposed to be resistant to vinegar, periodic use of this to decalcify the units only seems to hasten their demise.

The heads still pump fine and if one was pumping downwards to a holding tank as is the more usual arrangement, or had short length of hose above the pump, this would not be such a problem. However when pumping upwards with a 3' head, the bowls fill to the rim which is unpleasant especially in a seaway. The only solution is to keep rebuilding the pumps. Unfortunately the builder was also a strong believer in Lavac so installed the pumps out of sight, neatly located behind bulkheads and both the heads and bulkheads have to be removed in order to service the pumps. By the way, the Lavac manual recommends the installation of holding tanks above the pump height.

It seems the sailing community is strongly divided on Lavacs and I think the varying opinions are influenced by the installation - hose leading downward from the pump and easily accessible bulkhead mounting and they are OK and their merits of simplicity with few blockages win out.
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Old 12-07-2013, 12:42   #13
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Re: Lavac Head - Frequent Pump Rebuilds

Sorry to hear about your uphill pumping situation. I find it hard to believe that any flapper valve will hold off a head of 4' for very long. If you're just getting a little fluid back in the bowl I'd consider myself lucky. Our 9 year old Lavac has had nary an issue and the bowl stays bone dry IF I dry pump it. Why? Because my tank is in the keel and all the lines after the initial foot high loop go down hill. I hate fighting gravity.

best of luck in your quest for a dry bowl. Maybe a big shut off valve in the discharge line?
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Old 12-07-2013, 15:53   #14
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Re: Lavac Head - Frequent Pump Rebuilds

We also have a Lavac and a large above waterline holding tank.

We're also on our second pump. The first was so gummed up with papier-mâché that it would have taken a superhuman effort to rebuild so I brought a new Lavac pump. Not that much more expensive.

And we also have a backflow problem.

My solutions so far involve doing a fresh water flush when it gets a bit pongy, 3 toilet duck disks and putting a peg on my nose...
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Old 12-07-2013, 17:22   #15
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Re: Lavac Head - Frequent Pump Rebuilds

Yeah we do the fresh water flush too and always before leaving the boat. Still, the joker valve may last a few weeks or sometimes a year. We stopped using vinegar as that quickly kills the valves although supposedly shouldn't with nitrile - I wonder if the material is cheaper since the outsource to China. I have spoken to to Whale and to the US Lavac distributor but no solutions.

It might be OK if the pumps were accessible but they're not and I'm seriously thinking of installing the top rated Raritan Marine Elegance electric toilet. I notice several contributors to this site have dumped the Lavac for an electric head. Despite my best attempts at a "keep it simple philosophy" we already have 3" thick cable bundles in the boat so I suppose going electric for the head is not too much of an additional leap. I would keep one Lavac, mostly unused and loaded with fresh water.
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