problem with lavac

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dolphin

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good day,
recently have returned from my sailing holiday and everything was good except the problem with my very old lavac head:(
what is the problem - when pumping out the liquid everything is smooth without a drop of water on the lid but when coming to the hard stuff,
the inside of the bowl and the top lid/sitting are very dirty and need a good cleaning for the next use!
have changed the manual pump with brand new one but the result remain the same !
pumping out is ok, also the vacuum is quite good but the dirty remain! the situation is as a macerator pump is working inside of the bowl
the hoses from the toilet to the pump and from the pump to the sea cock are not more than 50-60 cm
the pump is about 50 cm higher than the sea level
what is wrong ?
any idea as in the many threads i have read, the problems are with blockage of the piping - inlet for flushing water, discharging line or the pump's valves.
the only thing, which come to my mind is to change the seals of the lid and sit for improving the vacuum
thanks
 
Are you sure the seals are not on upside down ? This is a bit of a long shot because usually if you install them wrongly there is very little vacuum. If you do order new seals make sure you inform the supplier that the bowl is the old design - they stopped making them in Stoke on Trent around five years ago and the new bowls are smaller.
 
to be honest, i am not sure, how the seals are fixed but the vacuum is quite good as after 10-15 strokes with the pump, need to wait about a minute before the lid open
 
the valves are working properly as the pump is new and there is no problem with pumping out the liquid with open or close lid
the water level is in the range of 10-15 cm
 
It does sound odd. Does it pump out ok with the lid open ? If so, that rules out the outlet. Also you have new pump. Maybe technique then but find it odd. Do you wait between each cycle ? ie, say 5-10 long slow pumps, wait 10 seconds then another 5-10 pumps.

Edit: During the waiting phase you should hear water trickling back in.
 
Last edited:
I had a similar problem when the pump inlet flap valve was gummed up with calcium crud causing the pump inlet valve not to close properly and blowing back into the lavac and spraying the underside of the lid.

Water pumped out OK when the lid was open.
 
it pump out perfect well with the old / new pump with the lid open
the pumping out was only with a sequence with about 10 strokes
the strokes were very sharp !
can this be the reason ?

Edit: During the waiting phase you should hear water trickling back in.[/QUOTE] - YES , i can hear the water


Storyline said:
It does sound odd. Does it pump out ok with the lid open ? If so, that rules out the outlet. Also you have new pump. Maybe technique then but find it odd. Do you wait between each cycle ? ie, say 5-10 long slow pumps, wait 10 seconds then another 5-10 pumps.

Edit: During the waiting phase you should hear water trickling back in.
Click to expand...
 
Last edited:
Dirty water can run back out of the pump into the bowl if the pump inlet valve is damaged or has something preventing it closing properly. Having been thro the valve into the pump & then leaked back out again it will, not surprisingly, appear to have been macerated.
 
dolphin said:
.....
the pumping out was only with a sequence with about 10 strokes
the strokes were very sharp !
can this be the reason ?

Edit: During the waiting phase you should hear water trickling back in.
Click to expand...

Yes, it could be technique. Now we have his 'n her heads I have to confess that sometimes if I have a wee in the evening during the beer drinking phase of the day I will only give a few short pumps. Subsequently, should swmbo decide to use 'my' heads she will complain I have not emptied it properly. Should point out that the morning ritual and the final wee of the evening are carried out with proper diligence ;)
 
Storyline said:
Yes, it could be technique. Now we have his 'n her heads I have to confess that sometimes if I have a wee in the evening during the beer drinking phase of the day I will only give a few short pumps. Subsequently, should swmbo decide to use 'my' heads she will complain I have not emptied it properly. Should point out that the morning ritual and the final wee of the evening are carried out with proper diligence ;)
Click to expand...

Put a lock on your heads! Before you know it, she'll be complaining about the seat position. ;)
 
it does sound as if waste is dribbling back into the bowl. i disassembled my pump and the valves are actually quite basic. the inlet is a simple flap and the outlet joker might just jam open with a bit of crud.

as its a new pump did it come assembled? i would be tempted to take it apart and see if the valves are seated properly.
 
dolphin said:
the hoses from the toilet to the pump and from the pump to the sea cock are not more than 50-60 cm
Click to expand...

60cm sounds a tad short if the thing is plumbed in with the proper loops in the pipework. I dont think it has any bearing on the problem though

dolphin said:
t the vacuum is quite good as after 10-15 strokes with the pump, need to wait about a minute before the lid open
Click to expand...

A minute is rather a long time. Are you sure the air bleed into the inlet hose is clear

sailorman said:
maybe you need to pump less vigorously, long slow strokes
Click to expand...
+1
 
I have a similar problem with our Jabsco if you go too hard at the pumping. Is your pump the Henderson MkV type? If so than after use the contents left in the pump body (water, etc) do tend to gravitate back into the toilet bowl after a while Check the water level in the bowl after you lift the lid and look again in 20 mins) This means that when you start pumping you are starting with an empty pump chamber and so the inlet valve on the pump has nothing to work with but air which can 'blow back' down the line to the bowl. The only answer as already stated are long slow pumps for the first 5 or so strokes and keep the valves clean and crud free during your annual service of the pump? It's probably just one of those things that once you know about you can live with.

Happy pumping....

Chas
 
qte
A minute is rather a long time. Are you sure the air bleed into the inlet hose is clear
unqte

-not sure for exact time it can be a little less
-the system is without the air bleed but just a valve on the inlet hose, which is closed after the pumping is completed !




VicS said:
60cm sounds a tad short if the thing is plumbed in with the proper loops in the pipework. I dont think it has any bearing on the problem though
A minute is rather a long time. Are you sure the air bleed into the inlet hose is clear
+1
Click to expand...
 
dolphin said:
qte
A minute is rather a long time. Are you sure the air bleed into the inlet hose is clear
unqte

-not sure for exact time it can be a little less
-the system is without the air bleed but just a valve on the inlet hose, which is closed after the pumping is completed !
Click to expand...
Not seen that before, on the three Lavac heads I have owned all have had a small plastic fitting with a pinhole fitted to he highest part of the inlet loop. Just what sort of valve do you have as this may be contributing to the problem ?
 
dolphin said:
qte
A minute is rather a long time. Are you sure the air bleed into the inlet hose is clear
unqte

-not sure for exact time it can be a little less
-the system is without the air bleed but just a valve on the inlet hose, which is closed after the pumping is completed !
Click to expand...

It should have an air bleed situated at the highest point in the loop in the inlet hose. Its purpose is to break the syphon and allow air to enter so that you can open the lid reasonably soon after use. The size of the vent hole (2 of different sizes are usually supplied) determines the volume of water left in the bowl. Lack of this vent is probably contributing to your problem as the retained vacuum is probably reducing the effectiveness of the flush and sucking excrement lodged in the pump back into the bowl with sufficient vigour to foul the underside of the lid.

See the Lavac user manual .... http://www.blakes-lavac-taylors.co.uk/pdf/lavac.pdf
 
VicS said:
It should have an air bleed situated at the highest point in the loop in the inlet hose. Its purpose is to break the syphon and allow air to enter so that you can open the lid reasonably soon after use. The size of the vent hole (2 of different sizes are usually supplied) determines the volume of water left in the bowl. Lack of this vent is probably contributing to your problem as the retained vacuum is probably reducing the effectiveness of the flush and sucking excrement lodged in the pump back into the bowl with sufficient vigour to foul the underside of the lid.

See the Lavac user manual .... http://www.blakes-lavac-taylors.co.uk/pdf/lavac.pdf
Click to expand...

+1

My thoughts exactly.
 
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