Help with Jabsco joker valve

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Oscarpop

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So, I bit the bullet today and changed the joker valve for the first time as it was starting to occasionally backfill.

Installed the new valve after checking it for holes or a poor seal.

However it is still backfilling, although really, really, really slowly.

I have taken it apart a couple of times now and can see nothing which would be causing this. There is no scale or interference that i can see either in the valve, or the way it seats.

Any ideas?

Its driving me spare.

Cheers
 
I would expect a degree of 'backfill' to be almost inevitable with the design of a joker. Presumably you have a discharge loop above waterline so maximum backflow is limited to the volume contained in the rising part of the loop. Isn't that why you pump enough times to ensure that only clean water remains to run back?
 
While I accept that a degree of backfill is acceptable, it never used to happen . Now it does.

The old joker valve stopped any backfill initially. Calcium buildup put pay to that.
 
I have come across the odd joker valve that didn't close properly, due to uneven surfaces, and you also need to be careful that the valve is correctly seated when tightening so that it isn't distorted. Even so, I don't think they can ever be relied on to be watertight.
 
johnalison said:
I have come across the odd joker valve that didn't close properly, due to uneven surfaces, and you also need to be careful that the valve is correctly seated when tightening so that it isn't distorted. Even so, I don't think they can ever be relied on to be watertight.
Click to expand...

+1.

Our local and renowned Loo Guru added a proper mechanical check valve ( non return valve) to the outlet puipe on ours when he fitted a new loo for us because our holding tank is mounted vertically and the loo outlet pipe to it goes some 8ft up to the top of the holding tank, so potentially 8ft of 1.5 inch dia 'water' column could trickle on back down. So we now have a Jabsco twist'n lock pump system, , then a normal joker valve ( called a 'duck bill' valve over here) then a bronze nonreturn valve all working on our side. [/smug]
 
As said, sometimes the lips in a new joker valve are slightly open. It may be that they will close after a short time under the head of water in the discharge hose. Wait a few days, if it doesn't happen you might consider replacing the valve again.
 
Inspect the lips carefully, if you can see any daylight though them, the valve will leak. There is rarely enough back pressure on them to ensure closure. (Unless you've got a ten foot anti-siphon loop). This coupled with manufacturing tolerances makes them inappropriate in this application but the fact that they cost a few pence to produce ensures their continuity. Having said that, most work ok but the ones that don't are irritating.
 
Many thanks. I will monitor it over the next few weeks.

In the mean time I ordered a whole new pump. I have issues with most of our current setup, and will just change everything and see what happens.
 
Oscarpop said:
Many thanks. I will monitor it over the next few weeks.

In the mean time I ordered a whole new pump. I have issues with most of our current setup, and will just change everything and see what happens.
Click to expand...

IF 'tis a Jabsco, I think a brand new new pump assembly might not include a new joker valve but if you are switching to a 'twist'n lock' from an original type that might help.
 
It might be the large flapper valve at the base of the pump cylinder not sealing when you lock the handle down. You can get these separately or they come in the service kits. Of course, your new pump will have one.
 
Ripster said:
It might be the large flapper valve at the base of the pump cylinder not sealing when you lock the handle down. You can get these separately or they come in the service kits. Of course, your new pump will have one.
Click to expand...

THe joker valve is the one that goes between the complete pump assembly and the outlet fitting with the pipe on it or am I dreaming?
 
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