Jabsco Toilet

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Ian_Rob

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Is there an obvious reason why a Jabsco WC that has been pumped dry should slowly fill again? I have just replaced the top valve as there was no incoming raw water on pumping and that is now working fine.

The system is switched to the holding tank.
 
Assuming it's a manual one that didn't do it beforehand, probably the joker or bottom flapper valve not sealing properly. Get a service kit and rebuild the pump (you get all the other wearing parts too) and this will prob solve it. This fault is not uncommon.
 
Did you get the spring in the top valve fitted? Without it can siphon on the inlet. Close the inlet seacock and see if it still happens. Otherwise it is backflow through the joker valve.

Twist and Lock pump will solve this,and not too much more than a service kit.
 
Ian_Rob said:
Is there an obvious reason why a Jabsco WC that has been pumped dry should slowly fill again? I have just replaced the top valve as there was no incoming raw water on pumping and that is now working fine.

The system is switched to the holding tank.
Click to expand...

You not say if its filling due to back flow of effluent, but presumably not, or with clean seawater.

Assuming the latter. It should not fill if correctly fitted with a vented antisyphon loop between the pump and the bowl. If it is not then that is half your trouble.

If the flush control valve is left in the correct position and working correctly that should also help to prevent syphoning. You final line of defence is of course the seacock

So firstly check your antisyphon loop and the vent valve at its highest point.

Secondly check/service the flush control valve.


If OTOH it is back flow of effluent then it indicates a poorly sealing outlet valve in the base, and a dodgy Joker valve. There should be a vented loop in the discharge pipe work which will prevent syphning.

As suggested a twist and lock pump should solve all backflow problems whatever the reason
 
VicS said:
If OTOH it is back flow of effluent then it indicates a poorly sealing outlet valve in the base, and a dodgy Joker valve.
Click to expand...

If you're in the habit of giving the toilet a good ol' flush after...errr..."light use" the back flow from a dodgy joker valve can look like ordinary seawater (because it mostly is...).
 
VicS said:
You not say if its filling due to back flow of effluent, but presumably not, or with clean seawater.

Assuming the latter. It should not fill if correctly fitted with a vented antisyphon loop between the pump and the bowl. If it is not then that is half your trouble.







As suggested a twist and lock pump should solve all backflow problems whatever the reason
Click to expand...
I have twist a lock which sometimes doesn't prevent backflow wonder which part controls this?
 
laika said:
If you're in the habit of giving the toilet a good ol' flush after...errr..."light use" the back flow from a dodgy joker valve can look like ordinary seawater (because it mostly is...).
Click to expand...

hopefully even after a "number 2" you'd flush it until only clean water remained in the pipework.
 
I can't understand all these problems with Jabsco s. I had one for 4 years and never any problems. No holding tank but I did flush paper down it. Are they made to a different standard now? The nrv s are pretty basic and should ideally be spring loaded.
 
pcatterall said:
I have twist a lock which sometimes doesn't prevent backflow wonder which part controls this?
Click to expand...
I have the twist lock model and had the backflow problem where the bowl fills to sea level (direct external connection). I bought the entire pump assembly and exchanged it, which cured the backflow ... for two years. Now I have the high bowl water level again. This same story happened with my previous boat when I replaced the old system for a twist to lock the joker valve down, it still needed replacing after a couple of years because of backflow.

It took Jabasco 30 years to think up the fairly obvious twist lock mechanism modification - perhaps it will take as long to properly perfect the system.
 
Barnac1e said:
I have the twist lock model and had the backflow problem where the bowl fills to sea level (direct external connection). I bought the entire pump assembly and exchanged it, which cured the backflow ... for two years. Now I have the high bowl water level again. This same story happened with my previous boat when I replaced the old system for a twist to lock the joker valve down, it still needed replacing after a couple of years because of backflow.

It took Jabasco 30 years to think up the fairly obvious twist lock mechanism modification - perhaps it will take as long to properly perfect the system.
Click to expand...

Sounds more like an installation error.
 
Barnac1e said:
I have the twist lock model and had the backflow problem where the bowl fills to sea level (direct external connection). I bought the entire pump assembly and exchanged it, which cured the backflow ... for two years. Now I have the high bowl water level again. This same story happened with my previous boat when I replaced the old system for a twist to lock the joker valve down, it still needed replacing after a couple of years because of backflow.

It took Jabasco 30 years to think up the fairly obvious twist lock mechanism modification - perhaps it will take as long to properly perfect the system.
Click to expand...

If the backflow fills the bowl to sea level or anywhere near it it must be syphoning rather than backflow as the discharge pipe probably only holds enough liquid to fill the bowl a couple of inches deep. If the water is clear it is syphoning from the sea water intake. If the water is foul it is syphoning from the holding tank although this is usually only possible if the tank is full.

Richard
 
VicS said:
If OTOH it is back flow of effluent then it indicates a poorly sealing outlet valve in the base, and a dodgy Joker valve. There should be a vented loop in the discharge pipe work which will prevent syphning.
Click to expand...

Why would you need a vented loop in the discharge pipe work if the system has a holding tank? Unless the holding tank is full right to the level of the inlet pipe I don't see how it could syphon as the holding tank is, in effect, the syphon break. Even if the tank is chock full presumably full it won't syphon for long 'cos the tank vent will break the syphon.

Richard
 
RichardS said:
If the backflow fills the bowl to sea level or anywhere near it it must be syphoning rather than backflow as the discharge pipe probably only holds enough liquid to fill the bowl a couple of inches deep. If the water is clear it is syphoning from the sea water intake. If the water is foul it is syphoning from the holding tank although this is usually only possible if the tank is full.
Click to expand...

Exactly. Installation error!
 
RichardS said:
If the backflow fills the bowl to sea level or anywhere near it it must be syphoning rather than backflow as the discharge pipe probably only holds enough liquid to fill the bowl a couple of inches deep. If the water is clear it is syphoning from the sea water intake. If the water is foul it is syphoning from the holding tank although this is usually only possible if the tank is full.

Richard
Click to expand...
No holding tank, no syphoning, outlet is direct to sea via Blakes seacock; bowl fills up to sea level. A new pump with new joker valve will seal for a year or two and bowl remains dry, then joker valve needs replacing as clear sea water begins ingress. Original installation by Hallberg Rassy 1981. Previous yacht had identical configuration, installed by Trapper Yachts 1980 and had identical symptoms despite complete new pump installation when turn and lock modification available.

It's supportable when moored or at anchor but prudent to close seacock when preparing for sea, although rarely is she heeled enough to put bowl under water level and entry is only at seepage speed anyway.
 
Barnac1e said:
No holding tank, no syphoning, outlet is direct to sea via Blakes seacock; bowl fills up to sea level. A new pump with new joker valve will seal for a year or two and bowl remains dry, then joker valve needs replacing as clear sea water begins ingress. Original installation by Hallberg Rassy 1981. Previous yacht had identical configuration, installed by Trapper Yachts 1980 and had identical symptoms despite complete new pump installation when turn and lock modification available.

It's supportable when moored or at anchor but prudent to close seacock when preparing for sea, although rarely is she heeled enough to put bowl under water level and entry is only at seepage speed anyway.
Click to expand...

If you changed the pipework, in line with Jabsco's instructions, you wouldn't have a problem. My HR352 had the toilet similarly plumbed incorrectly.
 
Barnac1e said:
No holding tank, no syphoning, outlet is direct to sea via Blakes seacock; bowl fills up to sea level. A new pump with new joker valve will seal for a year or two and bowl remains dry, then joker valve needs replacing as clear sea water begins ingress. Original installation by Hallberg Rassy 1981. Previous yacht had identical configuration, installed by Trapper Yachts 1980 and had identical symptoms despite complete new pump installation when turn and lock modification available.

It's supportable when moored or at anchor but prudent to close seacock when preparing for sea, although rarely is she heeled enough to put bowl under water level and entry is only at seepage speed anyway.
Click to expand...

If the bowl is filling up with seawater to sea level coming in from the heads outlet it must be syphoning back. I can't think of any other explanation. You need a loop with an anti-syphon valve. Any other solution, other than closing the outlet sea cock, will inevitably be hit and miss.

Richard
 
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