BACKFILLING TOILET ON OCEANIS 43

[Robert & Sandy]

Hello all,

The front head on our 43 has, after 6 years of perfect operation, begun filling with clean sea water after use; the only way to stop the inflow is to close the inlet seacock. I have replaced the joker valve, I feel fruitlessly as it is on the outlet side of the system.

Question: Is there a valve fitted on inlet side of the Jabsco 37010, as in the manual toilet, and/or do Beneteau fit an anti syphon or vented loop in their standard Oceanis toilet plumbing. I have had a reasonably good look and cannot find a fitted loop.

Regards,

Bilgolabands

[Mike Brown]

I'm assuming that you have the electric flush toilet. I'm also assuming that this happens even if you're sitting at anchor. So here are my thoughts.
The toilet worked fine for 6 years and nothing has changed other than the back flow so no need to make any modifications to your system, just some repairs. There is no vented loop on either of the toilets. There are only a couple of issues that will cause your problem. The first is a full holding tank which I'm sure is not your case. The second is a clogged vent tube which causes pressure to build in the tank pushing whatever is in the hose to backflow into the toilet. In this case you would get dirty water I'm sure. The third is the joker valve which you replaced already. Unfortunately some joker valves even when new will leak. I've found that if they are stored in such a manner that will distort them it can ruin it permanently. Try flushing and cleaning out the vent tube first. For a quick check simply loosen the deck cap to the forward holding tank and then flush, the tank will vent through the deck cap. If the problem still exists try replacing the valve again and see if that fixes the problem.
It's something simple I'm sure.
Good luck and let us know how you make out.
Mike
October Moon

[Robert & Sandy]

Hi Mike,

Thanks for your prompt suggestions.

Yes the Jabsco 37010 is the base model electric toilet.

Since posting I have examined the plumbing in closer detail and you are correct in saying there are no vented loops, simply short hose runs from the skin fitting to the pump.

I doubt if the holding tank has any influence as the flooding water is crystal clear sea water without any trace of even pipe scale or solids.

Do the US models have the large (40mm) vent in the topside which provides an aerobic atmosphere in the holding tank?.

I will check the hose attachment on the pump and if all else fails I will fit a vented loop and keep you posted

with results.

Thanks,

Bilgolabands

[James Taylor]

Great suggestions Mike!

If none of Mikes suggestions is successful I would disassemble waste line(s) from bowl to tank/overboard thru hull to check for blockage/buildup after  ensuring the electric ops switch is working properly.

If  line to  Y valve, or,  Y valve to tank line, or, Y valve to overboard through-hull line is blocked,  the bowl will fill when flushed. You could try to isolate which individual line is blocked but if any line in system is blocked with sea water by-product buildup it might be a good idea to replace them all.

[Robert & Sandy]

Thank you James.

I am really quite sure the trouble is in the in hose rather than the brown water out.

The latest theory here is the wear plate between the impellor and the housing may be worn causing  loss of the seal which is the only mechanical joint keeping the sea water out.

Bilgolabands

[Mike Brown]

Robert, it just occurred to me that another thing that you can do before you start making changes is to close the sea water intake thruhull when not flushing the toilet. If that eliminates your problem then you'll know it's definitely an intake issue. If you still experience back flow with it closed then you'll know it's coming from the tank side.
Good luck
Mike