More trouble with the Jabsco heads

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davidej

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We always seem to have problems with the bowl ‘back-filling’ ie the contents of the outlet pipe reappearing in the bowl. This has got much worse since we fitted a holding tank as the outlet pipe is now about 5 ft long with 3 ft vertical head before entering the tank.

Winter 2010/2011 we replaced the pump with a twist-and-lock and it was alright last season. However the backfilling has started again. I assume that the cause is calcification on the valves which stop them sealing properly.

Can anyone tell me
1. If I need only replace the joker valve or does the base valve need to be replaced as well
2. Am I likely to have any luck cleaning up the old ones with limescale remover – they look perfectly OK but have hard white deposits on them

Any other suggestions would be welcome.
 
davidej said:
We always seem to have problems with the bowl ‘back-filling’ ie the contents of the outlet pipe reappearing in the bowl. This has got much worse since we fitted a holding tank as the outlet pipe is now about 5 ft long with 3 ft vertical head before entering the tank.

Winter 2010/2011 we replaced the pump with a twist-and-lock and it was alright last season. However the backfilling has started again. I assume that the cause is calcification on the valves which stop them sealing properly.

Can anyone tell me
1. If I need only replace the joker valve or does the base valve need to be replaced as well
2. Am I likely to have any luck cleaning up the old ones with limescale remover – they look perfectly OK but have hard white deposits on them

Any other suggestions would be welcome.
Click to expand...


any back flow will be a duff joker
 
It has to be the joker valve. However, there is more than one way to make one leak. Calcium deposits in its housing can accumulate sufficiently to press on the valve, holding the lips open. After a while, perhaps dependent upon the above and whether any unusual chemicals have come into contact with the valve, it can suffer a permanent deformation that also holds the lips open.

A thorough clean up, using mechanical methods, is likely to be the best treatment. Chemical methods, using hydrochloric acid or products containing it, are best used on a regular basis to prevent accumulations. They cannot help with severe calcification.
 
Even if the backflow does get back through the Joker valve (which we know it shouldn't).. to make it to the bowl it would have to make it the wrong way past the lower wieghted flat valve as well..

One thing I have noticed with that lower valve is that even though it might look clean and the weight look clean and shiny... the flexible part of it sometimes stretches meaning that it will not settle back into place... Hold it up to the light and see if the gap opposite the hinge part of that valve is non existent as the flap overlaps the outer piece...
 
vyv_cox said:
I think you will find that when the joker valve is closed the base valve is open. The toilet wouldn't flush otherwise. Diagrams here.
Click to expand...

I cant get your link to open but have looked at the exploded diagram jabsco provide.

It seem to me that waste is drawn from the bowl into the lower pump chamber thru the flap valve, which closes on the down stroke and the waste is expelled out thru the joker.

Thus for backflow into the bowl to occur, water must pass thru both valves. Thats why I asked if I need to replace both of them
 
> I assume that the cause is calcification on the valves which stop them sealing properly.

As said above it sounds like the Joker valve. You can clean it but it's best to replace it. Assuming you do find calcium on it then take off the outlet pipe and bash it on a hard surface to get the calcium out. Also clean out the top of the throughull.
 
For water to flow back from the discharge pipe the joker valve cannot be closing properly.

However, the "twist and lock" feature should prevent the back flow even if the joker valve does not.

THEREFORE both the joker valve and the seal on the "twist and lock" feature are in need of attention.
It may or may not be possible to clean the joker valve and restore it to to proper operation. Replacement is probably the sensible option even if the old one is cleaned up and kept as an emergency spare.

IIRC there is an O ring on the bottom of the plunger assembly that forms a seal in the base unit when the "twist and lock" is engaged. That O ring probably needs repalcing and also the surface on which it should seal probably requires cleaning.

I am coming to the conclusion though that the twist and lock feature may not be all that is is cracked up to be! A good idea that for some reason does not work as well as it might.
 
davidej said:
I cant get your link to open but have looked at the exploded diagram jabsco provide.

It seem to me that waste is drawn from the bowl into the lower pump chamber thru the flap valve, which closes on the down stroke and the waste is expelled out thru the joker.

Thus for backflow into the bowl to occur, water must pass thru both valves. Thats why I asked if I need to replace both of them
Click to expand...

You are correct. In the static state both the base valve and the joker valve will be closed. They are opposed in the dynamic state. Sorry for any confusion.

I'm not sure how effective the base valve would be with virtually no head across it, so a small leakeage would probably occur, assuming the joker valve was leaking, even if the base valve was in good condition. On the many occasions that this has happened to me over the years, cleaning the joker valve has always stopped the leak.
 
Hopefuly by now you will have solved the problem, if not here is a solution;

I strip down the plunger and clean it.

2 remove the Joker and clean it

3 Make sure the waste pipe is clean.

4 remove and clean the flap valves.

When all of above is done put some OLIVE OLI in the piston and re-assemble.
Flush through with warm fresh water.
Pump the toilet dry Pour a little olive oil into the bowl and flush with fresh water

Remember it is 7 pumpms for every meter of pipe

Good luck

Peter
 
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Getting rid of the calceration

Having just done two, I would suggest that you remove the whole assembly and take it to a place where it can be more easily dismantled. Remember to both shut and secure th esea cocks, and arrange the pipes to get the open end well above the water line.

Physically remove as much of the crud, -you will be surprised how much is there, and then steep all the parts, valves and all in acid. I used the contents of a dead battery[ but remember to replace it with water as the scrap people pay you by weight for old batteries].

It will take at least 2-3 days of fizzing to get the parts clean and ready for re-assmbly. You may well not need a new set of valves.

It will also be much sweeter smelling, and take note of previous posts about olive oil, it doesn't need the sacrifice of a virgin, though.
 
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