Preventing crud in heads pump?

[Gazza]

Have just serviced the Henderson pump for our Lavac heads, finding the usual build up of brown crud in the body of the pump and all over the valves.
Although it's been three years (at least) since I had to do it, I wondered if there was any way of preventing the build up of crud, particularly on the outlet side. Any thoughts on using lanolin in the body of the pump and on the valves?
Just a thought.....

Gary Miller

 

[bigwow]

I put washing up liquid down mine every couple of weeks, seems to do the trick /forums/images/graemlins/laugh.gif

 

[VicS]

Brown crud? Usual problem is a limescale deposit which can be keept at bay flushing through with a cup of white vinegar on a regular basis.

 

[jerryat]

Agree with VicS. The 'Heads Specialist' - Peggy - recommends this method, and I can confirm that after following her advice and trying this method for the last couple of years (some spent full time cruising) it's worked brilliantly.

She may along in a minute to help out. Do try it - it saves hours of mucking around taking pipes off and 'banging' them out!

 

[Anonymous]

Is that 'crud' faecal, shortly after a flush, or is it scale-like (scrape it with a blade and one is squishy and the other is powdery).

 

[Gazza]

It's scale-like, probably about 5mm all around the inside of the pump body, with a significant build up on the outside of the outlet valve.
Like the idea of the vinegar - I'll give it a try.
Thanks to all,

 

[Anonymous]

Vinegar is a good ongoing treatment but if you have scale round the pump you very possibly have a heavily-scaled pipe interior like these....

<span style="color:blue">Courtesy jimbaerselman whose pictures they are, and the best examples I have ever seen
</span>
If you have this degree of scale you will never get it off with occasional vinegar - the best treatment (apart from removing and beating the pipes on the dockside) is to use hydrochloric acid. It is quite expensive in the UK high street (here in Spain it is about 70p a litre in all supermarkets!) but I believe that builders' merchants sell it as brick cleaner? I fill the toilet with hot fresh water to just under the brim, then add two UK-sized teacups of acid and pump it through slowly. I do this with our Jabscos and have no problems with compatibility so I doubt you will have any problems with the Lavac. If you do this overnight, leaving the acid in the pipe for several hours, the scale will come off.

 

[chasroberts]

Hi Lemain

Do you notice any adverse effects on the seals/pipework from the acid sitting in there overnight? I presume you are using agua fuerte?

Regards

Chas

 

[VicS]

[ QUOTE ]
I presume you are using agua fuerte?

[/ QUOTE ] I think you will find that that is nitric acid. In english that would be aqua fortis, an old name for nitic acid.

No reason why you should not use it if that is what you have access to but it is very much more hazardous to handle. It is also nearly 100% compared with concentrated hydrochloric acid which is only about 36% while brick cleaner is much less than that. So it would be appproriate to use much less than the 2 teacup fulls suggested.

I would be cautious about subjecting seacocks to regular doses of strong acids

 

[Birdseye]

Can you clarify. Do you close the seacock to keep the acid in the pipes. If so, how do you stop the gas given off bu**ering up the flap valve on your jabsco, or alternatively causing a bacvk flow as pressure builds up?

 

[Anonymous]

[ QUOTE ]
Do you notice any adverse effects on the seals/pipework from the acid sitting in there overnight? I presume you are using agua fuerte?

[/ QUOTE ]No adverse effects noticed but I haven't taken them apart for a long time (never service a Jabsco unless it doesn't work). Yes, I am using Agua Fuerte which, from the label, is HCl 24%.

If I ever have a problem with the Jabsco plastic parts I will replace them (and when I have run out of my spares kits, I will always replace the whole toilet, in future).

 

[Anonymous]

No, Agua Fuerte is HCl 24% or 15.5 degrees Be according to the label.

I know how not to use it, but not how to use it with caution /forums/images/graemlins/wink.gif I was worried about the effect on seacocks and have discussed it with various technical yachtsmen I have come across - mechanical, chemical and other engineers and the consensus is that the sea is always sloshing around in the seacock as long as it is open. I always treat mine open, never closed. The idea is to purge the line with acid (that's why I fill the toilet bowl with water and acid) but not to create a vessel. The seacocks feel fine and move very smoothly and seal well. I rather think that if there was a problem they would not move smoothly or seal well. What do you think?

 

[Anonymous]

I keep the cocks open. All I do is fill the bowl with hot water and pour in a couple of cups of acid, and pump until the bowl is empty (and a splosh of cheap cooking oil) and go to bed. In the morning the first one to use that toilet flushes through a few strokes to avoid getting a pickled bum /forums/images/graemlins/wink.gif We leave the agua fuerte bottle on the toilet lid to remind us.

 

[Richard10002]

As a matter of interest, (and perhaps safety), I wonder what the gas is that is given of when HCl is frothing with the limescale..... probably chlorine, and we should all be dead by now /forums/images/graemlins/confused.gif

and, more specifically..... do you "know" that your pipes are being kept clear, or are you merely confident whilst they keep working? (you've probably told us that they've been off at some point, and I've forgotten).

I only ask as, as soon as I bought Rogue, and discovered the limescale issue, I have been fairly religious with Vinegar, regular big flushing, flushing with fresh water before leaving the boat, and the occassional big froth with 100% limescale remover, (which I'm guessing is HCl of some strength)... yet, having removed part of one discharge pipe, it looks like one of Jims' examples.

 

[VicS]

[ QUOTE ]
No, Agua Fuerte is HCl 24%

[/ QUOTE ] Thats odd. Because the old English name for nitric acid is "aqua fortis" I assumed that was the same as agua feurte. An internet search seemed to confirm it. This is just one such search result. You'll notice that hydrocholric acid is "acido muriatico" which corresponds with the old English name "muriatic acid".

However if it is only 24 % it won't matter a great deal whether it is HCl or HNO3..

The problem in using any acid to remove a limescale deposit, and I assume that is what it is, is going to be keeping the acid in contact with the scale for long enough to dissolve it. It is going to take a little while, minutes I guess, not seconds or hours. Also the rection is going to produce CO2 so you cannot trap it in an enclosed space such as would be produced between a closed seacock and the non return valve on the outlet of the pump, as already pointed out. If you leave the seacock open then there will be a tendency for the acid solution to flow out because it will probably be slightly more dense than the seawater but in any case the build up of CO2 in the pipe will force it out.

All I can think of is pumping enough to largely fill the pipe, let that react for a while then pump another slug through and so on. Eventually you'll get it clean or at least clean enough.

To be honest I am not sure how bronze will stand up to a solution of a strong acid but brass is going to suffer some surface dezincification and DZR brass probably wont fair much better than "ordinary" brasses. Hopefully the seawater will wash it away before any harm can be done

Regular use of vinegar should keep the scale away once clean without any risk to seacocks. However Head Mistress has pointed out that acetic acid does soften rubber but I would think all the pump seals and valves are synthetic and not affected. It is something else to check I suppose.

 

[VicS]

[ QUOTE ]
I wonder what the gas is that is given of when HCl is frothing with the limescale..... probably chlorine, and we should all be dead by now


[/ QUOTE ] No it is carbon dioxide. Another one asleep at the back of his science lessons! /forums/images/graemlins/wink.gif Two simple ways in which chlorine can be produced. One is by the reaction between an acid, even a wek acid, and a hypochlorite. That is why you are always told not to mix hypochlorite based cleaners and bleaches with other cleaning agents. Hydrochloric acid and bleaching powder is a quick and simple way of preparing chlorine in the lab. The second method commonly used in the lab when a steady supply of chloine is required is by the reaction between concentrated hydrochloric acid and potassium permanganate. KMnO4 is a powerful oxidising agent which oxidises the HCl to Cl2.

Limescale remover could be any of a number of substances. A vigorous reaction would indicate a strong acid such as hydrochloric but a more gentle reaction could suggest sulphamic acid or any of a number of organic acids.

 

[Anonymous]

The gas given off in the reaction of HCl with CaCO3 is CO2

No, I don't take my pipes off to inspect them but we live aboard and have been since August 2004. I did have to take one pipe off in July 2005 and there was only the very thinnest scale on the inside.

I honestly don't rate vinegar and neither did my father who lived aboard for over 20 years and always used HCl (in his SL 401s) after bashing on the dockside for the first few years. After that he was never without a winchester of HCl

 

[Anonymous]

We have both stated confidently that the reaction with HCl produces CO2 however the gassing I experience is minimal. The same is true in our kettle. The 'limescale' we get in the toilet is, perhaps, not CaCO3 but some other calcium salt that does not liberate (much) CO2 when used.

As for the confusion in names, I can't comment...I have simply read from the label in front of me and confirm that everyone here calls HCl "Agua Fuerte" and I have seen it in different packaging. I suspect that the website is mis-informed or maybe the usage has changed over the years?

 

[VicS]

[ QUOTE ]
As for the confusion in names........ I suspect that the website is mis-informed

[/ QUOTE ] I have looked a number of websites now. I am in no doubt that Agua fuerte is strictly the name for nitric acid but I have also found a couple of retail products called agua fuerte that are HCl.

I will have to refer the misnaming of HCl to the EU bureaucrats to sort out.

Seriously you do have to double check what you are buying. Personally I think it is high time all these old names were scrapped. If you call hydrochloric acid hydrochloric acid and nitic acid nitric acid there is no confusion

If the scale in the toilet pipes does not fizz much with acid then obviously it is not entirely calcium carbonate. Calcium phosphate perhaps. The trouble will be that while calcium carbonate will dissolve quickly in acid what ever else is present may not are you are relying on the calcium carbonate bit to be dissolved so that the rest just falls away.

I would not expect much other than calcium carbonate in the kettle though.

 

[Anonymous]

I've just checked in my large (3kg) Oxford Spanish dictionary and it gives agua fuerte as nitric acid and shows no popular name for HCl simply acido clorhidrico. My bottle also has the word "Salfumant" directly above "Agua Fuerte" in such a style that the "Salfumant" could be a brand - but the brand is actually Bosque Verde, the own-brand of Mercadona (major Spanish supermarket) for their household products. Oxford gives Sal Fumante as HCl. Similar to our own "Spirits of Salts". I'm quite sure that when I first came across the product that I identified it by the side panel where it says acido clorhidrico but the product also says on the front panel "Usos: Limpieza de inodoros, desincrustante de cemento y cal, etc..." which has to be HCl and not HNO3.

Now I think about it, the kettle does fizz quite a lot, and the toilet fizz is not discernible.

Your observation about the toilet scale not being pure CaCO3 must be correct. I find that after treatment you can feel the roughness of scale powder in the pump (Jabscos) - it must fall back down the pipe. You have to pump it a bit to get rid of it or give a quick squirt of HCl, and that seems to clear it as well.

Do you know what the chemistry of the scale is? We know (or believe) that the decomposition of urine forms NH3 into solution and we think that this precipitates out the Calcium carbonate and bicarbonate - but as you say, that would fizz.

If we knew what we were trying to dissolve we might find a better solvent. This does explain why vinegar doesn't seem to do much - if the acid is breaking down a matrix of carbonate that is holding a greater quantity of some other salt in place, then we might expect the weaker acid to struggle. If it was calcium phosphate, what would be a good solvent? Maybe a chelant based product would be better than an acid?