Lavac Installation Pongy - Any ideas?

[LittleSister]

We've recently acquired a boat fitted with a Lavac toilet, and after a few false starts have now got it going. Was fine for a few days, but now emits a terrible pong. Not a 'fresh' waste smell, if you follow my drift, but reminiscent of sewage works.

The installation has Blakes type seacocks; bowl at or below waterline; inlet pipe is taken up to about 5 feet above bowl, and has a small hole made in it, presumably to break siphon, but curiously half way up the loop, not at the top, and there is an elbow to turn the tight corner into the rear of the bowl; outlet also loops up similar height, though no siphon break valve (is there any point to the loop without one?), with a Munster Simms Mark 5 pump at about 3 feet above the bowl.

Pump removes waste and draws water through, and when vacuum reduces sufficiently to open lid there's about half a bowl of clean water left (which we usually pump out with lid open to leave an inch or so). No obvious leaks.

All suggestions gratefully received.

 

[Searush]

There is sometimes some leakage back from the pump into the bowl. This is why the instructions say 8 steady pumps (shifts crop) pause (while bowl refills) and 5 more pumps (replaces soiled water in pump with fresh clean sea water now in bowl).

If sea water is left in the bowl for long periods the plankton in it will die & smell. Can't see any other reason for smells.

 

[simonfraser]

if you can see the exit, check how many strokes it takes to flush some paper out from the bowl, you'll be surprised. if you don't do that many strokes all the ***** will still be in the pipes & you wonder why it smells ?

 

[captainslarty]

Agreed with searush. it probably is a pumping problem.
Also try pumping some vinager through it. if that fails, take off the pipes and beat them to death on the pontoon to clear the crud out of them.
to control the level of water in the bowl vary the size of the hole in the pipe fitting small plug. (Dont BUY one - they are bic biro tops !) go slightly larger to lower the level. you shouldnt need to pump again after use to lower the water - also, keep the lid down.

 

[LittleSister]

Thanks for the suggestions, Searush, but I don't think it's either of those. Has had gallons of fresh seawater pumped through in last few days, both from use of the toilet and in a vain attempt to get rid of the smell.

 

[VicS]

I don't know why the air vent is not at the top of the loop, that's where it should be more or less.

The outlet pipe also has a similar loop. Normally the pump will pump enough air into there that it breaks the syphon so you wont get any water syphoning back even if the seacocks are left open and the pump valves let by a touch. (The person I crewed for did not shut the seacocks from the day he bought his boat in the mid 1970s until the day he died last year)

Bad odours are usually due to the effects of bacteria in the seawater on anything they can "eat". The pipework may not be the correct grade which is supposed to be impervious to smells.

It might be worth flushing through with some white vinegar.

You may not be pumping enough although if the installation is correct and the pump in good order you should be able to follow the instructions with no problems. Maybe the pump needs an overhaul.

The amount of water left in the bowl suggests that the air vent in the inlet pipe may be a bit restricted.(Or the wrong size of two alternatives fitted) Clean it and see if the volume is reduced. (A bristle from SWMBO's tooth brush is just the ticket for that!)

You can download the user manual from HERE

 

[LittleSister]

Thanks, Captain Slarty. We've been experimenting somewhat blindly with the size of the hole (originally was too large for the water to be drawn in at all and have experimented with partially covering it with tape). I'll try the vinegar trick, but most of the outlet pipe (all beyond the pump) is only a few days old as I had to replace that to get it far enough on the seacock to get double hose clips on as required by surveyor/insurer.

I'll try replacing remaining bit of outlet hose from bowl to pump (though as I said, it's not a fresh waste smell), and the whole of the inlet hose too (with siphon break biro top as recommended).

 

[VicS]

You could read Peggie Hall's book Get Rid Of Boat Odors, Peggie Hall (book ISBN: 1-892399-15-6)

 

[capnsensible]

Is it a sulphur sort of smell? If so, then this a common problem with all heads installations that are not frequently used. It will be the inlet side. The 'dead leg' of seawater contains animal/vegetable life that dies and causes the odour.
It should be possible to shut the hull valve, remove the inlet pipe so that you can rinse through with bleach, or simply replace the pipe if it is old. A hot air gun is extremely useful. Regular use of the flushing system prevents the smell.
The pump used has a non return valve so you wont get any smells coming back from the discharge side.
As these pumps are prone to furring up over time, my top tip is to carry a complete spare pump as well as a service kit. Then if the pump fails you can easily replace the broken one to be repaired at leisure. I have had the dubious priviledge of doing this countless times!!!!!

 

[LittleSister]

Thanks, Vic - knowledgeable and informative as ever.

Now I understand the lack of siphon break in the outlet, and am confirmed in my resolve to replace the inlet pipe and put a more sophisticated siphon break valve (if only a biro top - the existing hole looks like it was made with a bradawl!) at the top of the loop. I'll also replace the rest of outlet pipe as previously mentioned.

 

[capnsensible]

The reason there is no syphon break in the outlet side is that you would pump raw sweage out of ot into the boat!!!!

 

[LittleSister]

Thanks, Cap'n. I think the diagnosis is firming up. And in the event that I manage to resist throwing the whole lot over the side and reverting to bucket-and chuckit long enough to cure the pong, I'll certainly get a spare pump and service kit.

 

[Clyde_Wanderer]

When pumping out excess water with lid open, make sure there is enough water to come to a level above the top edge of the waste out spigot on the back of the bowl, I normally leave it about 1/2" above the shoulder of the venturi, as like with a domestic sink or wc the water acts as a water seal stopping smells comming up from the waste pipes.
Recommend you try it with a 1/3 of the bowl of retained water for a few days and if that cures the smell problem, you can graduly reduce the retained level until you find a happy medium.
Other than that you may have a leak somewhere along the waste pipework/pump etc.

 

[Clyde_Wanderer]

[ QUOTE ]
Agreed with searush. it probably is a pumping problem.
Also try pumping some vinager through it. if that fails, take off the pipes and beat them to death on the pontoon to clear the crud out of them.
to control the level of water in the bowl vary the size of the hole in the pipe fitting small plug. (Dont BUY one - they are bic biro tops !) go slightly larger to lower the level. you shouldnt need to pump again after use to lower the water - also, keep the lid down.

[/ QUOTE ]

Agree with above, but dont go too large with siphon hole as it causes some useless wasted pump strokes at the start of a pump out, I have left the hole small and prefer to pump out the excess water with lid open as you described, it also gives that extra little rinse.

 

[Bodach na mara]

The Lavac is a great toilet, and as others have said, your problem is likely caused by dead stuff in the inlet pipe. I get all sorts of stuff there, even mussels. You can also get a bit of a niff from the outlet, particularly if calcium deposits ("lime-scale") cause the valves in the pump to become less effective. That is where the vinegar trick is played.

The hole in the pipe is tiny. It is actually in an insert, like the end plug of a biro in shape. But the hole is so small that I do not have a drill small enough to drill one out.

 

[VicS]

The little air vents are available as spares. IIRC they come in packs of two, one each of two different sizes. They are just like the end plugs from Bic pens although I am not so sure that the pens have the same type of plug these days (Elf and safety cos kids could to swallow them!) I expect the installation instructions say what size hole to make in the pipe. The hole in the plug is pin hole size but Lavac have clearly determined what sort of size it should be for the system to work at its best.

(Don't do what one forumite did a year or two back and put the vent in the outlet pipe. He had to come on here to ask why he got sprayed with effluent every time he pumped the loo ... honest ... absolutely true.)

 

[hlb]

Right. Take note of all other sugestions, they all play a part. Espesially sea bugs in water. Find an empty spray bottle thingy. Go to pet shop. Buy some pet odore stuff. Fill Bottle and spray round offending area. Bilge usually. Problem gone.

 

[capnsensible]

Interesting concept. How does spraying something near the outside of a pipe solve the problem of whats inside the pipe??
Suppose oofle dust might do it...... /forums/images/graemlins/grin.gif

 

[captainslarty]

To cap it all, I am replacing the lavac with a Jabsco twist n lock system.. fed up of expensive henderson Mk5 pumps / service kits / blockages etc etc.
.
Anyone who wants a lavac come to Galicia and take it away for 50 euros - it will of course, be as new - spotlessly clean.. spare seal set for the whole unit too in a sealed box.

Its GOTTA go, otherwise, being porcelaine, it will deep six just fine..

 

[pmyatt]

In an older boat, the problem is almost certainly the hoses. You need double-walled sanitation hose to be sure of no pong.