Backfilling heads, normal?

[skyflyer]

Newbie question. I have only recently bought my own boat having previously rented etc. On previous boats I cannot recall seeingany issue with the bowl of the toilet backfilling - clearly seawater coming back from the outlet - provided the lever (Jabsco) is put over to the right hand side.

Other people have advised shutting off the outlet seacock every time we put to sea, but it is not that easy to get at, and of coure prevents use of the toilet when underway! (Not ever ideal, but sometimes ..just necessary!!)

Having studied the diagrarm in the manual and also a pack of spares, I see there is something called a 'Joker valve'. This seems to be like a tricuspid heart valve, ie the back pressure should seal it from back flow.

My question is, is it worth replacing this or is there always sufficient 'back-leakage' to allow a small trickle backwards. I dont really want to do what could be a pretty unpleasent job unless it is likely to make a big improvement!

By the way, the effect is worse when on a port tack, ( toilet is starboard side)

Any advise from you nautical sanitation experts would be handy!

Cheers

 

[oldvarnish]

You shouldn't get any back leakage. Almost certainly you need some new valves.
It's not a bad job. You'll find it remarkably clean in there and you'll end up with a good as new heads.

 

[Victoria Sponge]

We had the same problem. OH changed the seals, which sorted things.

 

[Bilgediver]

Newbie question. I have only recently bought my own boat having previously rented etc. On previous boats I cannot recall seeingany issue with the bowl of the toilet backfilling - clearly seawater coming back from the outlet - provided the lever (Jabsco) is put over to the right hand side.

Cheers

This is a good reason to fit an anti syphon loop . In fact it is a good idea to fit a loop in both inlet and outlet if this is a problem and not just hope the joker valve etc seats every time!

 

[Andrew_Fanner]

I had a not dissimilar issue last year, but from the holding tank, with the less than pleasant results of a bowl ful of filth. A mix of ignorance and cowardice prevented action on my part until Easter this year. MBM had a words and music article on servicing the head and accordingly I bought the appropriate service kit and followed the instructions.

Result: no backflow, easier working and very happy SWMBO and daughters. Win/win scenario Yes, its probably the joker valve but if that is knackered then other bits probably will be too. Expect to spend time descaling, its not a clean job but only takes a couple of hours. Close all seacocks first!

 

[johnalison]

Back leakage is a nuisance and some boats, like my old Sadler, have a loop in the outlet pipe which will stop this, as long as air is pumped through. The joker valve is actually bicuspid! and as old varnish says, easy to change. It may be worth changing all the bits while you're at it, or at least, having a look at them to familiarise yourself with the mechanism. Take care not to over-tighten the fastenings on the plastic.

 

[skyflyer]

The boat was built with a holding tank, but we ( I am a share owner) dont use it at present - i'm not sure why! It has a two way valve that allows the waste to go either directly overboard or to the tank. If it goes to the tank the tank has a vent which would - I assume - prevent any syphoning, The tank has a further discharge through a mecerator pump - - a different outlet than the 'direct waste'.

I understand the anti-siphon principle well enough, but how do you fit a loop without taking the boat trim apart to run it up above the water line? Sound slike a major job? At present it appears that all the pipes run along just below bench seat level in the saloon, which is pretty much waterline level -If we are on a port tack, it wont make any difference if the line is vented or not as the entire plumbing will be below waterline!

I will however fit a new JV and see if this helps.

 

[VicS]

The toilet should have antisyphon loops and valves in both inlet and discharge pipework. If it is not well above the waterlevel. They will prevent unwanted inflow. Difficult to fit maybe.

Note that the loop and valve in the inlet ( flushing water) must be between pump and bowl NOT between seacock and pump!

Replacing the joker valve, if its water coming back in via the discharge, should help.

The new type "Twist and lock" pumps should also prevent the back flow from the discahrge. Worth fitting rather than overhauling the old pump probably.

Better still fit a Lavac although the plumbing may also be a problem.

 

[cindersailor]

If you going to be taking it apart to replace the valve be carefull not to cross-thread the self-tapping screws when you reassemble, and be very careful not to over tighten them. The plastic mouldings are rather fragile.

 

[Fr J Hackett]

It is certainly the "Joker valve" that is leaking and often happens fitting an anti syphon loop and valve will stop the boat syphoning the sea into your boat but it will not stop the fluids in the section of hose between the bowl and the top of the loop (anti syphon fitted or not) emptying back into the bowl when the "Joker valve" becomes worn or slack I do not think you will be able to push air into the outlet section to stop the water in the pipe from flowing back. As Vic says fitting the newish pump assembly with lock down piston will do it at a cost of about £50, a service kit will cost about £25 to £35 depending on which you get. The advantage of the pump replacement is it's easy quick and does offer a permanant solution because inevitably the "Joker valve" will gradually wear and the problem represent itself and the cycle repeats. As you are new to marine heads I suggest that you insist when everyone uses them they do two things regardless of what it is they intend to pass into and deposit in the bowl:

SIT DOWN it save having to mop up peoples poorly aimed attempts.

Flush with copious quantities of water not just a couple of strokes. It reduces the build up of scale from the reaction of urine with sea water and the smell that one gets when people leave one in the pipe. You should be able to estimate the volume of pipe work you have and the volume that one stroke of the pump will give divide the latter into the former and you have the number of strokes required to clear the pipe work plus say 5 for good measure, on my boat that is 30 pump strokes. If you do that it will make future work on the heads a little easier!

 

[dt4134]

If you haven't got an anti-spiphon look you should fit one - welcome to the world of boat maintenance...

...but it may well just be calcium build-up on the joker valve. Last time I replaced mine but next time I plan just to descale it.

Brick cleaner (HCl) is good for that, but I got that advice from VicS via this forum. he's posted above so you could get it straight from the horse's (dragon's) mouth.

 

[vyv_cox]

Discharged bowl contents go through the joker valve, which is the name of the discharge valve at the foot of the siphon loop. Everything that passes the top of the loop falls down to the seacock and out to sea. Everything before the top of the loop sits there, held up by the joker valve.

If the valve leaks the column of 'water' will leak back into the bowl. The most common cause of valve leakage is accumulations of calcium salts on the lips of the valve. The easiest way to solve this is by dissolving it with hydrochloric acid, which many liveaboards do on a regular basis. Otherwise you can remove it and clean it, or just replace it.

 

[Andrew_Fanner]

I looked at the TwistnLock option and reckoned that £25 or so for the service kit plus 2 hours of my time was less than £70 for a new pump unit. IIRC you can just get the joker valve but I did the lot.

In passing I found that the macerator pump which is in the system is jammed up, so that's another job to do!

 

[skyflyer]

Fantastic stuff, thanks everyone.

I know about sitting down - new to boat ownership, not using boat toilets!

Jabsco manual suggests 7 strokes per metre of wwaste pipe, to ensure contents get fully discharged!

Time to get my hands dirty then!

 

[skyflyer]

I looked at the TwistnLock option and reckoned that £25 or so for the service kit plus 2 hours of my time was less than £70 for a new pump unit. IIRC you can just get the joker valve but I did the lot.

I didnt think it was possible to convert a non TwistnLock to become one, surely you need a new pump?

 

[theoldsalt]

Vyv,

Where can we get hydrochloric acid and how should it be use (concentration etc).

Jeff

 

[VicS]

Vyv,

Where can we get hydrochloric acid and how should it be use (concentration etc).

Jeff

Some patio, brick and masonry cleaners are hydrochloric acid based although by no means all.

Check the label before buying or check the Material safety data sheet.

B&Q are very good at publishing the info on line. I'd suggest checking their website for the data sheets of the products they sell and choosing one based on HCl.
Off hand I cannot remember which ones are HCl based and which are not.

 

[vyv_cox]

As Vic says you need to look at the data sheet for each product. There are two usual definitions, Brick Acid and Brick Cleaner. In most cases I come across the former one is the more concentrated. Jewsons sell Brick Cleaner, which is dilute, somewhere around 10%. Stronger stuff is available for example but a search will no doubt find more.

My boat is in the Med, where, at least in Spain, France, Italy and Greece, concentrated HCl is available in almost any supermarket. I use 1 litre per time to clean my toilet. I empty the bowl as much as possible, then put in 500 ml and pump a couple of strokes. The reaction can be heard as the CO2 bubbles quite strongly. I then continue to add the other 500 ml a bit at a time, pumping one or two strokes occasionally. Finally I add water slowly, trying to get the acid as far up the discharge pipe as possible.

HCl has no discernable effect on any parts, particularly because the whole job only takes 10 minutes, so exposure is minimal.

 

[theoldsalt]

VicS and Viv,

Thank you for that.

Viv - You seem to be saying that brick acid is at a much lower concentration than what you use. I assume therefore that I would have to leave the acid for much longer. If I can see/hear the reaction taking place, would it be ok to leave until it appears to finish - perhaps 30 minutes? Or should I just use more?

Jeff

 

[vyv_cox]

I just Googled a couple of Brick Acids, both were HCl at 18% concentration. I'm guessing, as the European stuff never states its concentration, that isn't a long way from being the same stuff. So I would give it a try as I suggest, leaving it a bit longer if it doesn't seem to be doing anything. It won't do any harm to increase the exposure.

I remember doing it one time in Olbia, Sardinia. The wind was blowing nearly 50 knots at the time but we could hear the bubbles coming out of the skin fitting from inside the boat, despite the noise of wind and rigging. The reaction can be quite vigorous!