vic008
Well-Known Member
Instructions are 10 strokes of the pump followed 5 sec later by 6 more. How strict are these rules? Just a recommendation?
Lavac head
- Thread starter vic008
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Old Harry
Well-Known Member
I now do 15 & 10 as long out pipe run
LittleSister
Well-Known Member
The rules aren't 'strict', but will affect how much water you have left in the bowl, etc.
srm
Well-Known Member
Depends on your pipe run. I have always used more than recommended to make sure the discharge pipe is clear. Seems to have avoided the build up of calcarious deposits other boats periodically have to remove. Experience based on around 20 years use of Lavacs on two boats.
VicS
Well-Known Member
The first bunch must be enough to ensure that all the waste is pumped out and the bowl is adequately flushed along with the outlet pipe. More pumps at this stage = better flushing
The second bunch are primarily to empty the bowl which otherwise may be left with too much water in it ..
The size of the air bleed in the inlet hose will affect the amount of water left ( two of the little inserts, of different sizes are supplied with a new toilet )
If you find too much water is left or it is taking too long for the vacuum to be released clean the pin hole.
LittleSister
Well-Known Member
Exactly so!
Boathook
Well-Known Member
About 10 to 12 strokes and then another 2 seems to work on my boat.
Old Harry
Well-Known Member
That is controlled by the size of bleed hole in the inlet pipe
ghostlymoron
Well-Known Member
It depends also on the length is discharge pipe. The aim is to flush clean the toilet and discharge pipe after each use. This will prevent a build up of crud in the pipework.
LittleSister
Well-Known Member
Actually, the combination of the bleed hole in the pipe and the second burst of pumping (i.e. how long the pause before hand, and the number/length/strength of pumps), as indicated by Vic.
(In fact, to be pernickety, plus also the particular qualities of the water inlet plumbing, which is why you might need different sized air inlet holes and/or to tweak slightly your pumping regime.)
vic008
Well-Known Member
And every session you are pumping away ,then have a hard to pump. Is this normal?
capnsensible
Well-Known Member
Nah. Quite likely a blockage. The recommended pumping regime works fine on most boats. But you will eventually find the outlet pipe internal diameter is drastically reduced by calcium scale. some wet tissue added to that and hey presto, blocked.
We have lived on our boat for over 20 years with a lavac and have been duty plumber more times than I ever wanted!
What we do. First, no tissue down the head. Ever. Goes into a plastic bag in a bin and emptied regularly. And lots of spray disenfectant. You will get some squirmy people but these are generally ones who have never unblocked one!
Weekly, I put a strong cleaner through to break up the calcium. Where we are, dilute hydrochloric acid is widely available real cheap. Since Ive been using that, touch wood, Ive never had to remove/replace the outlet pipe, at least over ten years.
And a top tip. The pump does sometimes get blocked, usually around the non return valve. I carry a complete spare pump. Can whizz the old one off and replace it in a few minutes. Then I can dismantle, clean and refit old one in slow time. Again, using strong cleaner regularly, its ages since Ive done that.
Oh, if yours is blocked and its not a new boat, its often easier to replace the outlet pipe with new rather than fannying about on the dock for hours trying to sort out the smelly old one.
Good luck!
Humblebee
Well-Known Member
A hard pump may be because of "solids" passing through the pump.
I'ts not a big job to take the front off the pump and have a look in to guage the amount of crud accumulated in there and if it looks clogged up, take the pump apart - fairly straightforward - and give it a good scraping out. Hoses might benefit from a clean through as well.
Edit - posted after Capn Sensible's good resume above.
I'ts not a big job to take the front off the pump and have a look in to guage the amount of crud accumulated in there and if it looks clogged up, take the pump apart - fairly straightforward - and give it a good scraping out. Hoses might benefit from a clean through as well.
Edit - posted after Capn Sensible's good resume above.
pvb
Well-Known Member
Are Lavacs falling out of favour now that so many boats are required to have holding tanks?
Muddy32
Well-Known Member
The sign opposite the Lavac on my boat says " Men sit down and 15 Pumps followed by a further 10"
I had thought that getting everyone to sing Happy Birthday twice through, will replace the instructions.
I had thought that getting everyone to sing Happy Birthday twice through, will replace the instructions.
vic008
Well-Known Member
The bleed hole in the inlet hose; dont think I have one. My inlet is about 9" long and at present am swapping the gate valve for a lever valve. I leave it open all the time.It must be above the WL. Will check pump. Firstly will give good shot of vinegar.Thanks
Boathook
Well-Known Member
If you are pumping into a holding tank you only need to do enough pumps to shift the toilet contents there.
VicS
Well-Known Member
Both hoses should loop well above the water line.
The inlet hose should have a pin hole air vent in it at its highest point. The pin holes are in little plastic inserts that look like the little end caps in some brands of ball point pens. It is not particularly obvious
The whole way in which a Lavac works is based on this pin hole. Without it you will always end up with far too much water left in the bowl and it will take a long time for the vacuum to decay before you can open the lid .
If the toilet is below the water line the air vent also breaks the siphon. Air being pumped into the outlet hose prevents a siphon forming in the outlet.
If the toilet is above the water line water won't siphon in therefore it is possible for the inlet hose not to loop but a pinhole is still needed to break the vacuun and control the volume of water left in the bowl ... It is possible to put the pin hole in the toilet lid in this case .
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Babylon
Well-Known Member
I've used mine faultlessly for 13 years: 8-10 pumps followed a few seconds later by 5-6, but its a small boat with short runs.
Never had a pump blockage, but never put any paper into the bowl; use biodegradable nappy-bags which go into the bin.
Finally, when putting the boat away, I always put a small squirt of washing-up liquid into the bowl before pumping dry then closing the seacocks. I imagine some detergent then remains in the pump and - as well as lubricating everything - helps break down deposits or any other muck?
Never had a pump blockage, but never put any paper into the bowl; use biodegradable nappy-bags which go into the bin.
Finally, when putting the boat away, I always put a small squirt of washing-up liquid into the bowl before pumping dry then closing the seacocks. I imagine some detergent then remains in the pump and - as well as lubricating everything - helps break down deposits or any other muck?
rogerthebodger
Well-Known Member
This is a blockage I had in my Lavac outlet pipe.
