Jabsco manual toilet inlet water supply, fresh ?

skipper_stu said:
Sorry, am with Vyv on this one. Have just spent two days rebuilding and refurbing one ready for an article in the mag. the big piston that you pump up and down, the bottom piston side pulls the cack out of the bowl on the up stroke in to the pump, then pushes it out through the joker valve on tne down stroke. The top side of the piston meanwhile pulls the bowl flush water in to the pump on the top side of the piston on the down stroke and pushes it to the bowl on the up stroke. The piston housing that is doing all this is thus contaminated by cack on the up stroke along its full length. If you are daft enough to connect your freshwater system to the flush connection inlet then there is the possbility of cack germs migrating through the flush valve back to the fresh water system! This is the reason that water companies and the law now insist that there be a physical break between contamination and the water mains, you will have seen the result because marinas now dont allow water hoses to be connected permanently on pontoons. Also building regs? insist on physical breaks in domestic properties!
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I think we are agreeing then
 
I'm tempted to go with the theory posted by Vyv and others, because my Lavac does not suffer from the smell issue. There is no reasonable way the inlet pipe can be contaminated.

The reason i hesitate is, i also have a sea water pump in the galley. I don't really use this pump, but if i should happen to give it a pump it smells just like the old Jabsco on my previous boats. So i'll be interested to hear why this is :confused:
 
PaulRainbow said:
I'm tempted to go with the theory posted by Vyv and others, because my Lavac does not suffer from the smell issue. There is no reasonable way the inlet pipe can be contaminated.

The reason i hesitate is, i also have a sea water pump in the galley. I don't really use this pump, but if i should happen to give it a pump it smells just like the old Jabsco on my previous boats. So i'll be interested to hear why this is :confused:
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I don't think its one or the other I think both theories are correct for the two reasons.

Both are due to decay of organic matter as you can get the same effect with Vyv's theory and with decay of minor organisms in the water.

My reasons are I also have a lavac and when left for some time I can get the loo smell and the inlet and outlet are on different sides of the keel.

I also have a Jabsco converted to electric using a pressure pump for inlet water and a diaphragm pump on the outlet again with inputs on different sides of the boat.

My sea water foot pump also has the same smell when first used.

When I am on the boat fore some time the smell goes away with long pumps to completely flush the outpipe in both heads.
 
I suggest that the source of the seawater plays a part. When I carried out the tests to determine whether the smell was from seawater alone I used water drawn from out at sea, where it stood a reasonable chance of being uncontaminated. There is a strong chance that water taken from harbours and marinas will be contaminated (do you always walk to the toilets in the middle of the night?), not necessarily with Stu's cack, but with some other organic stuff.
 
vyv_cox said:
I suggest that the source of the seawater plays a part. When I carried out the tests to determine whether the smell was from seawater alone I used water drawn from out at sea, where it stood a reasonable chance of being uncontaminated. There is a strong chance that water taken from harbours and marinas will be contaminated (do you always walk to the toilets in the middle of the night?), not necessarily with Stu's cack, but with some other organic stuff.
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Quite right Vyx, I don't think that you can always guarantee the same cause in such poorly controlled "tests" (i.e. What someone noticed on his/her boat).

I don't think that there's anything magical about fresh water either. It is possible that a sudden change from salt to fresh causes enough pressure across cell walls to cause damage but that's just a guess. It certainly seems true that moving between salt and fresh for a while does kill off existing hull growth (I used to do that twice a year and noticed the effect). I find that my fresh water flush does work but I also include some bacteriocide from time to time.

I also agree that the pump can cause cross-contamination. However, this is limited to the section between the base of the pump and rim of the bowl where water flushes through. I don't see the contamination finding a ready route back down from the flush side into the incoming seawater pipe. Any contamination would be quickly forced back as flushing continues. A more likely route would bewater from the outlet skin fitting being sucked into the inlet pipe and this has been said many times in earlier discussions.
 
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The following might be of interest:

Forward head on my boat:
No holding tank
Rarely used for anything other than a pee (probably 2-3 times in 9 years)
Used several times each day (2 persons on board, 6 months each year)
Always flushed a fair bit (approx. 24 strokes to cover 2-3m of pipe
Outlet and inlet fittings approx. same distance and orientation as aft. head
So nil faecal material, only pee and well flushed.
O-ring lubed with silicone grease very 6 weeks (5 min. job).
It does develop a smell if untreated. It was a lot worse when we weren't living on board but does still smell eventually. I fitted a T-piece to allow me to flush the inlet hose every 6 weeks and the problem vanished. I did forget this year and the started to notice a smell after 8+weeks, not much to be honest but enough for my wife to ask me to clean it.

Aft. head
Rarely used for a pee unless at sea and holding tank is open
Minimal flushing when holding tank in use.
Copious flushing at other times (+30 strokes after emptying tank)
Outlet and inlet fittings approx. same distance and orientation as fwd. head
Certainly likely to have faecal contamination via pump (visibly so on odd occasion)
O-ring lubed with silicone grease less frequently (still 5 min. job after copious flushing).
Never had any sign of rotten egg smell from this head.

So one does have a tendency to smell if left untreated and the other one doesn't (and not the one you'd expect either). I've never felt the slightest need to fit a fresh water flush to the aft head.

All this ever told me was that no single source of contamination was guaranteed to explain all smells relating to heads.
 
Mistroma said:
The following might be of interest:

Forward head on my boat:
No holding tank
Rarely used for anything other than a pee (probably 2-3 times in 9 years)
Used several times each day (2 persons on board, 6 months each year)
Always flushed a fair bit (approx. 24 strokes to cover 2-3m of pipe
Outlet and inlet fittings approx. same distance and orientation as aft. head
So nil faecal material, only pee and well flushed.
O-ring lubed with silicone grease very 6 weeks (5 min. job).
It does develop a smell if untreated. It was a lot worse when we weren't living on board but does still smell eventually. I fitted a T-piece to allow me to flush the inlet hose every 6 weeks and the problem vanished. I did forget this year and the started to notice a smell after 8+weeks, not much to be honest but enough for my wife to ask me to clean it.

Aft. head
Rarely used for a pee unless at sea and holding tank is open
Minimal flushing when holding tank in use.
Copious flushing at other times (+30 strokes after emptying tank)
Outlet and inlet fittings approx. same distance and orientation as fwd. head
Certainly likely to have faecal contamination via pump (visibly so on odd occasion)
O-ring lubed with silicone grease less frequently (still 5 min. job after copious flushing).
Never had any sign of rotten egg smell from this head.

So one does have a tendency to smell if left untreated and the other one doesn't (and not the one you'd expect either). I've never felt the slightest need to fit a fresh water flush to the aft head.

All this ever told me was that no single source of contamination was guaranteed to explain all smells relating to heads.
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I still think its a combination of cack juice leakage and organisms in sea water trapped in the flush sea water pipe rotting away.
 
Minchsailor said:
I can never understand this problem with smelly pipes. Fresh water is too valuable to use in flushing the loo.

Just pump LOTS of sea water through every time it is used, and dose with bleach when leaving the boat - it has never failed me.
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Which is fine, provided you are just pumping out direct to the sea, which is forbidden where I sail, and should be forbidden in bays and harbours everywhere. If you have a holding tank pumping LOTS of water just fills it up too quickly.

As for contamination of the fresh water tank, it just does not happen because the water is pumped in, in my system, by a dedicated electric pump, which is effectively a pair of non return valves in tandem. Even if it could contaminate the tank it would not matter as the boat has two and one is used to supply the heads, and the other for washing. We never drink water from the tanks because tap water here in Turkey is often unsuitable and nearly everyone drinks bottled water.
 
My ideal design of head would have a dedicated pump out pump with no connection to the water inlet, and direct water supply to the bowl. Perhaps the best design would have a macerator pump fitted directly under the bowl, and a separate electric inlet pump.
 
Norman_E said:
My ideal design of head would have a dedicated pump out pump with no connection to the water inlet, and direct water supply to the bowl. Perhaps the best design would have a macerator pump fitted directly under the bowl, and a separate electric inlet pump.
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These already exist.
 
skipper_stu said:
I still think its a combination of cack juice leakage and organisms in sea water trapped in the flush sea water pipe rotting away.
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I believe that I pretty much agreed with you. Either one or the other or both together depending on conditions in the system. The problem becomes a lot worse when the contamination is in the inlet hose. Recirculation of faecal matter by the pump is more easily cleared and needs no mods. to the flushing system.
 
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vyv_cox said:
I suggest that the source of the seawater plays a part. When I carried out the tests to determine whether the smell was from seawater alone I used water drawn from out at sea, where it stood a reasonable chance of being uncontaminated. There is a strong chance that water taken from harbours and marinas will be contaminated (do you always walk to the toilets in the middle of the night?), not necessarily with Stu's cack, but with some other organic stuff.
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Yes, I suggested that the clean Aegean seawater (ISTR) you used in your test lacked either enough natural organic matter and/or enough bacterial 'seed’ to get natural H2S production going, so it was not proof that that faecal matter was needed.

All that is needed on top of natural organic matter (of perhaps entirely non-faecal origin - dead algae etc.) is a seed of aerobic bacteria - to use the organic matter as food and thus deplete the oxygen - and a seed of anaerobic bacteria - which ‘take over’ when the oxygen runs out, using sulfate from the seawater as an alternative oxygen source and so producing the H2S.

I was going to get round sometime to doing an incubation test with organic-rich estuary water, in the expectation of being able to demonstrate that. But as contributors to a later thread (http://www.ybw.com/forums/showthrea...of-the-inlet-pipe/page5&highlight=heads+smell) referred to getting H2S with other intakes distant from the heads, and in a heads that had never received faecal matter, I haven’t bothered.

Of course faecal cross contamination may often be the source of the organic matter and the bacterial seeds – but it does not have to be, and knowing that may be helpful in putting the issue in perspective.
 
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Hydrozoan said:
Yes, I suggested that the clean Aegean seawater (ISTR) you used in your test lacked either enough natural organic matter and/or enough bacterial 'seed’ to get natural H2S production going, so it was not proof that that faecal matter was needed.
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The original purpose of the test was simply to debunk the theory that the degradation of seawater alone was the cause of smells. My results have now gone on to be used for purposes outside the original brief.
 
vyv_cox said:
The original purpose of the test was simply to debunk the theory that the degradation of seawater alone was the cause of smells. My results have now gone on to be used for purposes outside the original brief.
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Your website used to say, of your Aegean water incubation experiment: ‘I conclude from this research that hydrogen sulphide in sea toilets does not occur by degradation of seawater. It seems far more likely to be due to contamination by human waste.’
http://www.ybw.com/forums/showthread.php?432535-Heads-inlet-pipe-smell/page9&highlight=smell+aegean

That has been understood to mean that hydrogen sulphide in heads derives from faecal matter, and not from seawater – see for example http://www.ybw.com/forums/showthread.php?422563-No-More-Smelly-heads&highlight=debunked)

In fact, whether the carbon food source for the bacteria is faecal or non-faecal the hydrogen sulphide does come from degradation of the seawater sulfate. (There will of course be some sulfur in the organic matter, but it’s the sulfate that acts as the oxidizer in the anaerobic step, itself being reduced to hydrogen sulfide.)

In some cases the organic source may indeed be faecal cross-contamination, but in others a transient odour may derive from natural organic matter and it would be unfortunate if skippers, concerned about any notion of faecal contamination, should be unaware of that possibility.
 
Hydrozoan said:
Your website used to say, of your Aegean water incubation experiment: ‘I conclude from this research that hydrogen sulphide in sea toilets does not occur by degradation of seawater. It seems far more likely to be due to contamination by human waste.’
http://www.ybw.com/forums/showthread.php?432535-Heads-inlet-pipe-smell/page9&highlight=smell+aegean

That has been understood to mean that hydrogen sulphide in heads derives from faecal matter, and not from seawater – see for example http://www.ybw.com/forums/showthread.php?422563-No-More-Smelly-heads&highlight=debunked)

In fact, whether the carbon food source for the bacteria is faecal or non-faecal the hydrogen sulphide does come from degradation of the seawater sulfate. (There will of course be some sulfur in the organic matter, but it’s the sulfate that acts as the oxidizer in the anaerobic step, itself being reduced to hydrogen sulfide.)

In some cases the organic source may indeed be faecal cross-contamination, but in others a transient odour may derive from natural organic matter and it would be unfortunate if skippers, concerned about any notion of faecal contamination, should be unaware of that possibility.
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I think you are splitting hairs. Yes, any organic sulfate compound in the water has the propensity to degrade but my work showed that samples taken from the open sea did not contain these.
 
vyv_cox said:
I think you are splitting hairs. Yes, any organic sulfate compound in the water has the propensity to degrade but my work showed that samples taken from the open sea did not contain these.
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I'm sorry Vyv, but I don’t believe I am and your reference to 'any organic sulfate compound in seawater' is completely baffling to me.

The only sulfate in seawater to which I refer is the inorganic sulfate ion – a major seawater anion, and what anerobic bacteria employ to oxidise carbonaceous material. Nothing whatsoever to do with organosulfates.
 
Norman_E said:
My ideal design of head would have a dedicated pump out pump with no connection to the water inlet, and direct water supply to the bowl. Perhaps the best design would have a macerator pump fitted directly under the bowl, and a separate electric inlet pump.
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sounds like a lavac where there's a positive pump out pump, flushing water is drawn in by vacuum - no common pump.
 
Mistroma said:
Quite right Vyx, I don't think that you can always guarantee the same cause in such poorly controlled "tests" (i.e. What someone noticed on his/her boat).

I don't think that there's anything magical about fresh water either. It is possible that a sudden change from salt to fresh causes enough pressure across cell walls to cause damage but that's just a guess. It certainly seems true that moving between salt and fresh for a while does kill off existing hull growth (I used to do that twice a year and noticed the effect). I find that my fresh water flush does work but I also include some bacteriocide from time to time.

I also agree that the pump can cause cross-contamination. However, this is limited to the section between the base of the pump and rim of the bowl where water flushes through. I don't see the contamination finding a ready route back down from the flush side into the incoming seawater pipe. Any contamination would be quickly forced back as flushing continues. A more likely route would bewater from the outlet skin fitting being sucked into the inlet pipe and this has been said many times in earlier discussions.
Click to expand...

The contamination happens because the O ring piston has cack juice on one side as it pulls and pushes out of the bowl and the rinse water on the other side of the piston. The piston tube has cack juice smeared up and down it as the piston is pumped up and down, think about it!
 
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