Jabsco Electric Conversion - will the boat flood?

Richard10002

Richard10002

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Hi,

Fitted the above, connecting the original hoses to the same places on the pump, (if that makes sense).

I now find that, after we have flushed and emptied, the bowl fills to what seems like the outside water level, and I can hear a hissing at the siphon whilst it is filling. If I put my finger over the hole in the syphon thing, the bowl stops filling. I thought the syphon thing was supposed to stop this happening?

Could there be a problem with the syphon thing, or have we fitted the pump wrong.
 
Where is "the siphon thing" (vented loop?) installed--between thru-hull and the pump, or between the pump and the bowl? How high is it?

If you can provide a photo of your installation, I should be able to see what the problem is.
 
Which siphon break: inlet or outlet. 3/4" or 1 1/2"

If you are making the problem stop by putting your finger on it, the problem would seem to be elsewhere.

Did you put back the rubber valve in the 1 1/2" outlet pipe? It does not seem to be part of the conversion kit. Was it damaged?

Also where are you? The yard seemed empty last time I was there.
 
[ QUOTE ]
Where is "the siphon thing" (vented loop?) installed--between thru-hull and the pump, or between the pump and the bowl? How high is it?

If you can provide a photo of your installation, I should be able to see what the problem is.

[/ QUOTE ]

Not sure how to do photos yet and guess it will take a while to set up... so I'll try and describe:

The inlet from the sea is a yellow and black corrugated pipe 3/4"? and it is attached to the tube near the bottom of the pump.

The pipe between the pump and the bowl is white 3/4"? and is attached to the tube near the top of the pump... the vented loop has white pipe in and out of it.. so i assume this is the pipe between the pump and the bowl, i.e. the vented loop is between the pump and the bowl.

The loop is just below deck level and about 105cm above where it connects to the pump and the bowl... the bowl connection is towards the top of the bowl.

The outlet from the pump to the sea is a yellow and black corrugated pipe and is attached to the bottom of the pump where the jokjer valve is.

I hope this makes sense.... if not, I will set up the photo thing and post a few.

Many Thanks

Richard
 
[ QUOTE ]
Which siphon break: inlet or outlet. 3/4" or 1 1/2"

If you are making the problem stop by putting your finger on it, the problem would seem to be elsewhere.

Did you put back the rubber valve in the 1 1/2" outlet pipe? It does not seem to be part of the conversion kit. Was it damaged?

Also where are you? The yard seemed empty last time I was there.

[/ QUOTE ]

see my reply to Headmistress for a description.. it seems to be the siphon break between the pump and the bowl... I cant see any other siphon breaks, but this doesnt mean they dont exist <g>

The yard fitted it, so I'm not sure which rubber valve you mean.. having taken the manual one to bits, serviced and refitted it, the only valve I can think you mean is the Joker valve, which was new a couple of weeks before the conversion. This doesnt mean it isnt damaged... just that i dont think it is.

I'm in Glasson Dock on pontoon 3, 2nd on the left. Pontoon 3 is the one directly ahead of you if you turn right out of the shop - why? are you here? which boat... where?

Cheers, and thanks for the help.

Richard
 
You said, "The inlet from the sea is a yellow and black corrugated pipe 3/4"? and it is attached to the tube near the bottom of the pump."


If your toilet is the 29200 conversion shown here...

http://www.jabsco.com/prodInfo/overview/43000_0504_10_02.pdf

...I can't be sure without seeing it, but I THINK I may know what your problem is...'cuz the inlet hose should be connected to a fitting at the TOP of the pump (see the drawing on page 2 of the link).

The wet/dry knob should also be left in the dry position...never in the wet position.

It has nothing to do with your current problem (though it will create other problems soon), but sanitation hoses should be smooth walled, never corrugated.
It's forgiveable that an owner may not know that, but not a yard. It's so basic that I'm worried about what else they've done wrong...at least one thing for certain, 'cuz your bowl is flooding. I'm especially worried now about how they wired it...whether they ran a separate dedicated circuit, shared by nothing else that can pull power away from the toilet--low voltage will damage the motor and also cause sluggish discharge--as they should have done, or just spliced into the nearest wire. Which in turn raises the question of whether they made sure the wire size is adequate for the distance--always measured round-trip, btw) from the battery. That toilet is a real power hog...it draws a whopping 24 amps--50% more than most other macerating electric toilets--so it needs a BIG wire AND it needs to be on its own circuit.

So check your installation against the instructions at the link above, and if ANYthing doesn't match the specs, make 'em do it over. And DON'T let 'em bluff you that something doesn't matter...'cuz ANYTHING that isn't done according to the instructions WILL cause problems sooner or later.
 
[ QUOTE ]
You said, "The inlet from the sea is a yellow and black corrugated pipe 3/4"? and it is attached to the tube near the bottom of the pump."


If your toilet is the 29200 conversion shown here...

http://www.jabsco.com/prodInfo/overview/43000_0504_10_02.pdf

...I can't be sure without seeing it, but I THINK I may know what your problem is...'cuz the inlet hose should be connected to a fitting at the TOP of the pump (see the drawing on page 2 of the link).

The wet/dry knob should also be left in the dry position...never in the wet position.

[/ QUOTE ]

OK... the pipes are fitted correctly... The inlet is connected to a pipe which comes out of the bottom of the upper pump, and the bowl feed comes out of the rear of the upper pump, horizontally.

What confused me was a plastic 90 degree plastic joint which looked like a pipe coming from the bottom of the pump, (there is no pipe coming from the bottom of the pump).

The wet dry knob springs itself to a central position. If it is twisted to wet, or dry, the pump operates.

The wiring is correct as I provided it, and it's route, myself - having asked lots of questions here. I also have a 35A breaker switch close to the battery.

So the problem, if it is a problem remains. after flushing, the bowl fills to what I think is the waterline, and stops filling if I put my finger over the pump-bowl vented loop.

My thoughts were that it might be a problem with the loop, which I think has a flap in it?

Thanks again

Richard
 
More questions...

Your toilet is below the waterline...right? And there's no vented loop in the discharge line...right?

If you close the DISCHARGE seacock, leaving the intake seacock open...does the toilet still fill?
 
[ QUOTE ]
More questions...

Your toilet is below the waterline...right? And there's no vented loop in the discharge line...right?

[/ QUOTE ]

Yes and yes, (as far as I can tell)

[ QUOTE ]
If you close the DISCHARGE seacock, leaving the intake seacock open...does the toilet still fill?

[/ QUOTE ]

Yes. If I empty the bowl, then close the discharge seacock quickly, the bowl fills just the same as before.

Over to you!

Many Thanks

Richard
 
I do wish I could see it for myself!

Two final quesions--one of which I meant to ask in my last post: if you close the INTAKE seacock, leaving the discharge thru-hull open, does the bowl fill?

What make/model toilet did you "convert?"
 
So as far as I can see everything plumbing wise is correct. Although I have strong dislike also of the pipe materials.

You said originally "after we have flushed and emptied". With the assumption that since both pumps are driven off the same motor the only way that Jabsco can not pump flush water is by sealing off the inlet to the flush pump (i.e. the dry/flush valve). This would also explain the rule of not doing it for long. (there is another way; by letting in air but I think that would cause leaks and drips)

If this is the case then what ever happens there is still about 1.6l of water in the pipe from the siphon break to the bowl. This will always fall down into the bowl. This is an estimate assuming your siphon break is just below deck level.

The only way to test this theory is to "flush" then wait a while for the level to stop rising and then "empty". Is there is a difference afterwards?

If this is the case then it looks like the air into the siphon break is far too small for your installation. If the siphon break let in a lot of air the water from the downward leg would get to the bowl before you had finished the empty cycle. If the siphon break is one of those black plastic ones then take out the rubber bit and check that the valve is correct. Also check that the top has not been tightened too much.

For your system to work the siphon should break and the pipe empty within the same length of time the switch is put to the dry position. A few seconds.

This is all assuming a lot, and could be total rubbish but give it a try. Next time I am up there I will come and see you.
 
[ QUOTE ]
I do wish I could see it for myself!

Two final quesions--one of which I meant to ask in my last post: if you close the INTAKE seacock, leaving the discharge thru-hull open, does the bowl fill?

What make/model toilet did you "convert?"

[/ QUOTE ]

It still fills, but perhaps a bit more slowly?

Model converted 29090-0000
 
We need to address two things...the first being the water rising in the bowl via the discharge:

When any toilet is below the waterline, vented loops are needed in both the intake AND the discharge. Water is rising more slowly via the discharge only because the joker valve is new and is slowing it down...as the joker valve becomes worn, water will rise in the bowl to the waterline a lot faster and can flood the boat. So it's essential that a vented loop be installed in the discharge ASAP. Also keep BOTH seacocks closed while underway except when the toilet is being used...'cus a vented loop won't prevent water from being pushed in the bowl via an open thru-hull. And ALWAYS close the seaocks when leaving the boat...open head thru-hulls when no one is aboard is a leading cause of boats sinking in their slips.

Now about the water in the bowl via the intake: I was mystified that putting your finger over the hole in the vented loop stopped it till I read Neils theory and remembered something: if you fill a drinking straw with water, the water will remain in the straw as long as your finger covers the top of it...falls out when you remove your finger.

So I think Neil is onto something with his theory that the water in the bowl in the bowl from the intake is only the water left in the line between the top of the loop and the pump...how much water depends on the length of the line. It could very well be enough to fill the bowl to approximately the waterline. Flushing in the discharge mode should empty the bowl and it shouldn't refill.

However, Neil's theory that the hole in the vented loop is too small doesn't work...if that were the case--if it's not breaking the siphon started by priming the pump when you flush, putting your finger over it would make no difference...the siphon would just continue.

So Richard, I want you to try a little experiment: Close the intake seacock and remove the hose from the thru-hull. Stick it in a bucket of water...flush the toilet till the bucket is empty. IMMEDIATELY close the DISCHARGE seacock (this may require a second person) to prevent any water from rising in the bowl via the discharge. If the water you've been seeing in the bowl is only the water left in the line between the top of the loop and the pump, the same thing should happen to the remainder of the water from the bucket...and it should empty when you flush in the discharge mode. But if NO water rises in the bowl when the intake line is off the thru-hull, I confess--I'm STUMPED!
 
HeadMistress: Because Richard said originally that it looked like the water level came up to the same as the outside I would assume that the siphon would break really quickly even if the hole is small.

The entry to the bowl is at the top of the bowl and so the difference in heights across the siphon must be small or negative. This would be about right for a Moody.(Obviously when sailing it would be different)

So say the hole lets in 2l/min. The first seconds would be enough to break the siphon and then it would take 10s of seconds to empty the pipe. He described it as a "hissing" noise which means the air is quite restricted like a bike puncture. I think your straw idea is correct but instead of taking your finger off the end put a pin through the wall and puncture it. Blakes Lavac vacuumed flush uses a type of tiny air hole to break the siphon.
 
We ALL assumed that because the water apparently rose in the bowl to the waterline, it had to be a siphon....that's what had all of us--me included--mystified. But I'd bet real money that you nailed it correctly when you suggested that it's only the water left in the line between the top of the loop and the bowl...that it's only a coincidence the volume is enough to put it at the waterline.

You said, "The entry to the bowl is at the top of the bowl and so the difference in heights across the siphon must be small or negative."

I'm not sure what you mean by that. On ANY boat vented loops have to be at least 6-8" above waterline at any angle of heel, which puts it 3-5' above the toilet on any boat when the boat is at rest.
 
Peggie & Neil

Thanks for all the help... it's a lot of food for thought. I'm leaving for Portugal 13/8 and will have little time aboard before then, so I wont be able to action any of the suggestions/recommendations.

However... I'm hoping that we are only talking about residual water, in the pipe on the inlet side, and in the pump on the outlet. It definitely didnt do this when the manual was fitted so, as a last resort, I could alwasy refit the manual.

Anyway... we have 2 heads, (one manual as originally fitted), so I will test the electric when we get to sea and have some heel on, (there will be 5 on board, so plenty of hands for seacocks). If it fills/floods, we can have a rule where we dont use it at all if necessary.

I can see a loop for the discharge, (almost at deck level like the pump/bowl pipe), but I cant see the vent, so I'll get onto the Moody Owners site to see if it is an awkward spot, or if there isnt one.... It's hard to believe there wont be one, as they are evrywhere else that they should be.

Thanks for the help.... I'll keep you posted, probably in a few weeks on this topic.

Richard
 
Richard, I suspect that the bowl on your manual toilet didn't fill because you left wet/dry lever in the "dry" position, blocking the flow of water from the inlet hose. But there's no way to do that on the electric conversion, so the hose drains.

If there's loop in the discharge, it's a vented loop. Any water left in that line will run downhill back into the bowl too.

Have a safe trip to Portugal...and do let us know what you find after you've gotten back and had time to mess with things on the boat again.
 
Understood.

The plan is that we are not coming back, (not for a few years anyway!). We're going to liveaboard and see where we get to.

I'll be keeping an eye on the loo, but it wont be a top priority <g>

Thanks for all the help so far.

Richard
 
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