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[alandav123]

Hi all, does an Lawrence SL400 sea toilet need to be afloat with both sea cocks fully open to work properly?

My boats ashore just now and I decided to strip down the toilet and do some maintinance ( it has never been that great but I was hoping that was due to me not been able to know when the inlet sea cock was fully open as the handle had fallen off) so I was guessing it.

Today I refitted the SL400 and immersed the inlet hose into a bucket of seawater and pumped it like mad to no avail, I primed the bowl with a bucket of seawater to help get it going but although it eventually emptied it was splashing out at me etc....its either knackered OR as Im hoping it needs to have the hydrostatic pressure up into the inlet valve and also perhaps the vacuam created by he larger flow of water getting forced down the outlet to the sea.

If its knackered I am going to rip out the thing and install a cassette type campervan one which I already own so it free, the diaphraph repair kits are silly money to buy so its a dormobile special if the SL400 had given up the ghost.

 

[VicS]

It might have difficilty lifting water very high from a bucket until it is primed but it should pump out with no problems.

Id think probably both inlet and outlet valves need overhauling

I'd not have thought parts were "silly money" compared with what some things cost. You can but take it apart, determine what parts are needed and work out the cost of the overhaul.

All parts lists diagrams and manuals on the SL Spares website

 

[alandav123]

Hi there, I had a look at the spares list and Id still stick with "silly money" £48 for a toilet seat....I dont think so.

what I did notice though was that the inlet hose is suppossed to be straight into the rear of the toilet at roughly the same level (plane), mines has been fitted with a huge loop as is supposed to be used for the outlet. Wondering if it does not have the " wellie" to suck up all the way around a big anti syphoning loop which is bringing the whole thing to a hault.

regards Alan

 

[Stemar]

It seems to me that you want a short run from the inlet seacock to the pump than a loop with anti-syphon valve between the pump & the bowl then another loop with anti-syphon between the pump and the outlet seacock.

A loop with anti-syphon between the inlet seacock and the pump is doing just what it's designed to do - keeping water from being sucked through the inlet! the anti-syphon is designed to be where the pump creates positive pressure - not negative.

 

[alandav123]

Steve I think your right, to be clear both loops are simply that "large high loops, when I said anti syphon I was aying that as a general term rather than as a specifiec piece of kit.

Perhaps its designed that the seawater almost "flows" into the bowl with very little encouragment and the heart of the system and the power part is in the forceing everything up & out.

regards Alan

 

[pampas]

Two things that make the toilet less able to function,

1.. that the spring loaded valve it the correct way round.

2.. That the Joker valve outlet "Lips" have not relaxed.

Regarding a high inlet loop also the exhaust loop, I have brought mine about 8" above the waterline and this has totally stopped waste water back filling into the bowl, The down side is that one has to pump a few extra strokes in order to flush. Well those are my observations.

 

[VicS]

Steve I think your right, to be clear both loops are simply that "large high loops, when I said anti syphon I was aying that as a general term rather than as a specifiec piece of kit.

Perhaps its designed that the seawater almost "flows" into the bowl with very little encouragment and the heart of the system and the power part is in the forceing everything up & out.

regards Alan

If the loop betwwen the inlet seacock and the pump has been fitted with an antisyphon valve at to top of the loop that could well be your trouble ... it's sucking in air!

The normal way of plumbing the inlet water for a toilet located below the water line is a short direct connection from the seacock to the pump and then a loop with an antisyphon valve between the pump and the bowl.

I am not sure if it is possible to fit a loop between pump and the bowl in the case of the SL400.. the instructions do not seem to show it as a possibility.

 

[alandav123]

To Pampas

The joker valve...if that was weak would that explaine the poor clearance rate and the splashing back at me when I am pumping it too...if so thats worth trying to change as its a tenner.

As to the other working parts, it would seem quite a challange for a layman to strip out and decide whjats good or bad when looking at the bits for the first time.

The joker valve may ne a go'er though.

Regards Alan

 

[ostell]

The SL400 is a nice bit of design but when the cost of spares is more than the cost of a new toilet of other makes then it's time to think about it. I became adept at changing things on them, my latest boat came with a spare SL400 in a box but I bit the bullet and got rid of it for a Jabsco.

The SL400 should suck up the water IF all the valves are in good condition. Try cleaning the rubber with vinegar to get rid of deposits then oiling them with vegetable oil.

I have had a maintenance kit where some bits were 1mm oversize but sufficiently so so that the darn thing wouldn't work. Got the correct size bits from another source and everything worked.

 

[rob2]

Take heart. If the thing used to work and you strip and clean all the parts it'll probably work again. I've had a loo start to froth the content rather than pump out and simply cleaning the joker valve sorted that! (Marigolds are your friend). I also have a loop between inlet seacock and pump - note this can never use an anti-syphon valve - and found that by pushing the loop down horizontal the pump can prime itself, no problems thereafter.

Sadly as the unit is obsolete you should expect the spares to be more expensive than those for a current model. However, compared to the prices charged for things like engine gaskets, they're not so silly! It saves a lot to know the base engine number...

Rob.

 

[ianat182]

My original toilet was an SL400 and the fault you mention was infrequent but almost always caused by the thin steel spring on the flap valve that rusted away. After two replacements I made up my own from stainless steel wire that lasted for 4-5 years when I replaced the SL toilet with a Plastimo one that virtually fitted in place of the other; at £75 from (dare I say it-Marine Megastore!!) it was a good deal with new plastic hoses, however there are two size seats for the model, mine is really too small with hindsight.

ianat182

 

[Burnham Bob]

The SL400 was often installed when there wasn't much height. It was the only one that fitted my old boat the Halcyon 23. There are complete overhaul kits available from a guy who used to work there.

The inlet was controlled by pusahing the handle over to the left when facing the toilet and getting that to work and then cut off the inflow was a problem on mine. So i used to open and shut the inlet sea cock to control the flow of water in and out.

New boat has a Lavac that's much easier but the SL400 was perfectly adequate.