LAVAC - Help/Advice needed

[Scotty_Tradewind]

Lavac has stopped drawing in water.

It flushes o.k.with the normal 10 strokes (with a generous top up from a bucket), but in the second phase where you pump again for 5 strokes, no water comes back into the pan...???

I've turned the seacocks to closed and pulled a vacuum and then opened again hoping it may clear something and I've filled to the brim with a bucket several times to see if things will prime, but so far no luck.

Help!! so far on first 3 weeks on way towards Scotland and it gets a bit of a fag to do the bucket journey in a seaway.
I have comprehensive tools aboard and rubber gloves,( snorkel and mask ).... but stupidly no internal spares for the Lavac.

S.

 

[sailorman]

Lavac has stopped drawing in water.

It flushes o.k.with the normal 10 strokes (with a generous top up from a bucket), but in the second phase where you pump again for 5 strokes, no water comes back into the pan...???

I've turned the seacocks to closed and pulled a vacuum and then opened again hoping it may clear something and I've filled to the brim with a bucket several times to see if things will prime, but so far no luck.

Help!! so far on first 3 weeks on way towards Scotland and it gets a bit of a fag to do the bucket journey in a seaway.
I have comprehensive tools aboard and rubber gloves, snorkel and mask.... but stupidly no internal spares for the Lavac.

S.

Why do you have to add extra water
what seacocks do you have . if gate valves the spindle might be stripped & not opening the gate

 

[rob2]

You really do need to check whether the seacock is opening (fully). If possible attach a length of hose to get above the waterline so you can open the cock and rod through to check.

I had difficulty priming my Jabsco after servicing, it will depend on how your plumbing runs. Being pretty much on the waterline, I have an anti-syphon loop between the seacock and the pump, though obviously no valve. This was too much of a head for the pump to prime so I pushed the loop down to the cabin sole to reduce the head and all worked fine - and has continued to do so with the loop back in place. I'd advise you to sort it out with the boat relatively level on the mooring, which sounds quite a likelihood with the weekend forecast!

Rob.

 

[tillergirl]

Something suspicious about needing to add a generous top up from a bucket to flush. Will it not discharge everything without adding more water? There are really only three things to go wrong - the pump, the seals and a blockage. If the pump discharges the contents of the bowl with the lid up, that would seem that the pump is ok. With the lid down it seems a vacuum is formed from what you say so that implies that the pump and seals are ok and only leaves a blockage on the inlet, either something in the pipe, the inlet or the seacock not opening as has been said.

 

[vyv_cox]

Chuck it out and buy a Portapotti! Top advice from another current thread.

 

[alahol2]

With the lid down it seems a vacuum is formed from what you say so that implies that the pump and seals are ok and only leaves a blockage on the inlet, either something in the pipe, the inlet or the seacock not opening as has been said.

If the vacuum is formed and holds for 10 - 15 seconds then agree fully with Tillergirl. You've got a blockage on the inlet somewhere.

 

[VicS]

If the vacuum is formed and holds for 10 - 15 seconds then agree fully with Tillergirl. You've got a blockage on the inlet somewhere.

And it could be at the inlet to the bowl or in the water passage in the top of the bowl... Someone on here recently had a similar problem.
Poked a bit of wire in IIRC and cleared it

Take the pipe off the bowl inlet and see if it will still pull a vacuum . If it does the problem is in the bowl.

It is pulling a vacuum I take it ... not defective seals on the seat or lid allowing air in

If that is clear look at the hose , the seacock and also check the strainer on the outside of the inlet seacock

 

[penfold]

Is your syphon break working?

 

[condor]

When I bought my boat I discovered the inlet strainer was blocked. Managed to clear it by removing the inlet hose from seacock and blowing out through the opened seacock with the dinghy pump, then a quick close of seacock and refitted inlet hose. I later cleared it fully when out of water.

Check the lid/seat seals are ok creating a vacuum, the syphon break insert is ok in the inlet hose (ie hasn't dropped out, allowing too much air in), and the inlet hose connections are not drawing air.
Not much else to go wrong really on the inlet side except as someone else said there could be a blockage at the pan inlet itself.

Good luck.

 

[Frankie-H]

I have lived aboard, very happily, with 2 lavacs, for the last 16 years.

If you are not getting water into the bowl:

Does the pump become more difficult to pump and is the seat being pulled downwards by the vacuum. In this case you have a blocked inlet, strainer probably.
Possibly jellyfish or something pulled into the inlet pipe

If the pump is easier to opperate and you might hear some hissing. Then you probably have a damaged lid or lid seal.

The seals in the pump itself are not high tech. You have a flapper on the inlet and a pelican on the outlet. If the flapper valve has broken, you would suck water into the bowl and push it out through the same valve on the outstroke.

PM me if you wish, with more symptems and I can probably help.

 

[Frankie-H]

The 2 phases, you mention, do not have anything to do with pumping in or out. The pause in the middle is simply to allow the bowl to fill with more water. Under most circumstances but not, apparently, with yours.

 

[LittleSister]

The pause in the middle is simply to allow the bowl to fill with more water. Under most circumstances but not, apparently, with yours.

I thought the pause in the middle was to allow less water to remain in the bowl. As I see (hear?) it:

a) When you initially start pumping it's pumping out but there's no water coming in yet ('cos you've got to draw it all the way up the inlet with the vacuum first);
b) Water then starts flowing in and you're flushing through (pumping in and out simultaneously);
c) After 'enough' flushes, you pause. This allows the water to recede back down the inlet (due to the siphon break);
d) A last few flushes removes (pumps out) most of the water from the bowl, but no more comes in because you haven't pumped enough to draw the water all the way up the inlet again.

Am I wrong?

 

[Boathook]

I thought the pause in the middle was to allow less water to remain in the bowl. As I see (hear?) it:

a) When you initially start pumping it's pumping out but there's no water coming in yet ('cos you've got to draw it all the way up the inlet with the vacuum first);
b) Water then starts flowing in and you're flushing through (pumping in and out simultaneously);
c) After 'enough' flushes, you pause. This allows the water to recede back down the inlet (due to the siphon break);
d) A last few flushes removes (pumps out) most of the water from the bowl, but no more comes in because you haven't pumped enough to draw the water all the way up the inlet again.

Am I wrong?

Yes with d. my lavac draws in water on the last few pumps but takes more out.

If the op's is not 'sucking' water back in check the lid and seat. I had a problem where the lid seal was coming out and letting air in. It seemed that lavac had problems with this caused by the ring holding the seal in place. For me pushing the ring back in sorted this out for a short while, but in the end I restuck the ring to the lid. Another problem is when the seat is not square on the pan, again letting air in.

 

[Scotty_Tradewind]

now in Isle of Man and due to weather hav holed up in Peel.
Had time to get the seals off and give the already clean loo an even more thorough 'birthday'.
Having washed the seals and grooves in the lid with washing-up liquid, I dried them and gave the grooves agood spray of silicone to prevent the seals from sticking inside the grooves.
I also stripped the hinge mechanisms tg discover that they are handed and had been assembled on the wrong sides. This probably allowed too much left and right sloppiness in the lid and seatto form a seal when down.
First try.... 'perfect'.
I've also sent for and been sent some new seals .... I've been told that Lavac are in receivership... hope stocks of spares last!

 

[dutyhog]

now in Isle of Man and due to weather hav holed up in Peel.
Had time to get the seals off and give the already clean loo an even more thorough 'birthday'.
Having washed the seals and grooves in the lid with washing-up liquid, I dried them and gave the grooves agood spray of silicone to prevent the seals from sticking inside the grooves.
I also stripped the hinge mechanisms tg discover that they are handed and had been assembled on the wrong sides. This probably allowed too much left and right sloppiness in the lid and seatto form a seal when down.
First try.... 'perfect'.
I've also sent for and been sent some new seals .... I've been told that Lavac are in receivership... hope stocks of spares last!

Glad you got it going on route without need for spares. One season we had a similar fault, and it was due to too much antifouling over the inlet strainer that I hadn't noticed before launching.