Jabsco Pump Problem

[emandvee44]

Last year I installed a holding tank system, having read all the PBO articles and advice from the equipment suppliers.
I purchased a Tek-Tanks custom (my) design tank, jabsco diverter valve, 2 anti siphon loops, a y connector, a 2” plastic ball valve, hull vent, deck pump out, leesan charcoal filter, Whale discharge pump. The 2” waste handling hose is the flexible type with helical wire re-inforcement.
The installation incorporates the existing 2” outlet sea cock, and sea water inlet.
Soon after ‘commissioning’, I was pumping the toilet (direct to sea), perhaps rather more vigorously than usual when the pump seized up. I dismantled the pump cover to check the flapper valve but all was in order. Then I disconnected the joker valve cover and found the joker valve had turned inside out. I replaced the valve with a new one assuming that the old one had failed, and all was well for a while. However some time later the same thing happened again, and it seems to only occur when pumping hard. It would be difficult to live with this problem permanently and have to tell any user that ‘gentle pumping only please’ and knowing that a failure in certain circumstances would be very messy and unpleasant to resolve.
I have included images of the installation which might help.
Any suggestions greatly appreciated.
Michael.

 

[Resolution]

I'm struggling to understand how a joker valve can turn inside out. Is the flap valve not seating properly and allowing back pressure on the suction stroke?
Or have you fitted the joker valve back to front?

 

[Steve Clayton]

U have a blockage or a breather issue somewhere on the outlet side. As u pump it's building up pressure beyond the joker valve; the back pressure gets to a point where it turns the joker inside out.

 

[GrahamM376]

U have a blockage or a breather issue somewhere on the outlet side. As u pump it's building up pressure beyond the joker valve; the back pressure gets to a point where it turns the joker inside out.

Agreed, it's happened to ours. Have you used any of the old pipework? Flexing it around can break the calcium deposits off the wall and they can block the heads outlet pipe even a few days afterwards. I had this happen after I'd changed the through hulls.

 

[jon711]

Definitly a restriction or blockage on the outlet side, this causes a build up of pressure aginst the joker valve and inverts it. Usually you can just "un-invert" it and reinstall (although that doesn't solve the problem).

Congratulations on the instalation, that is one of the nicest I've ever seen (Believe me I've seen a few, at boatshows guess who would be tracing the pipework around the boat!)

It dosn't look like an installaton problem, possible that the diverter valve may not be diverting correctly, unusual, but I have managed to dismantle these and re-assemble incorrectly (ie the through path rather than from toilet to seacock is actually internally switched from holding tank to sea cock.

Pipework looks new, so I would doubt any build up of calcuim.....

Cann't think of any other reasons at present..

Jon

 

[emandvee44]

Jabsco pump problem

Thank you for the replies so far, which might provide the answer!
All the pipework is new, and the only old parts are the hull fittings, sea cocks and hose tails.
It is possible that some debris lodged behind the sea cock, as the hose tail is 90deg. and therefore I could not see inside it when I fitted the new hose.
I am going to change the sea cock as it is very stiff.
Another thought. The anti-syphon valve allows a syphon break and thus a water/liquid head against the joker valve. Perhaps the head is just too much.(from memory about 1.5m)

Cheers,

Michael.

 

[jon711]

Another thought. The anti-syphon valve allows a syphon break and thus a water/liquid head against the joker valve. Perhaps the head is just too much.(from memory about 1.5m)

QUOTE]

No, 1.5m meters would be fine, in fact less can cause more problems. Having that much head on the joker valve actually helps it to seal and reduce back flow into the bowl. Does the tank empty through the seacock OK? if so then would doubt a slight blockage on the seacock, but that may be the case....

I would be very tempted to investigate the diverter valve, or even try bypassing it to see if the problem re-appears..

Jon

 

[MoodySabre]

Very nicely done My first thought was the outlet seacock.