Jabsco Head Bubbling

[TravellingKiwis]

Hi .

Before posting this I have read through the other threads on bubbling but after trouble shooting but would still appreciate any advice in case I have missed something

I have a 10 month old Lagoon 42 with 3 x Jabsco Quiet Flush 37245-1692, the system layout is as per this attachment. It is salt water flushed using A Jabsco Par Max 4.

Attachment 196215

One of three toilets is bubbling and it only started recently. The bubbles are large, take a little while to start after flushing and then after a while they stop. The bubbles are clear with no indication of waste backflow. There is no hissing / pressure noise associated with the bubbling.

The vent/overflow pipe from the top of the tank is large enough that I have been able to run a garden hose pipe all the way up it from outside until all the hose water went into the tank. There is no indication of any type of blockage or pipe restriction.

Access to the tank is in the shower and the removable panel is sealed on three sides ... so I've not removed it ... yet.

The tank has been open and empty for days so to trouble shoot further, I filled it completely up until water escaped from the vent / overflow pipe, the flow rate was high so again no indications of blockage. When emptying the tank the waste water flow rate is high and constant without any gulping. Interestingly, the toilet bubbles even when the deck pump out fitting is removed which indicates this can't be a blockage causing a tank pressure issue.

I have removed the pump and cleaned it. Whilst doing so I could hear the air coming from the waste pipe through the joker valve. I removed the waste pipe and joker valve, cleaned it and put it back together (no spares onboard).
Once everything is back together the toilet stills bubbles.

After the waste pipe exits the toilet, I am unable to see or access it until it nears the tank but I suspect that it runs downhill at some point before running up to the top of the tank.

So ... my naive first time troubleshooting of a marine toilet and my hypothesis is that the toilet pumps some air into the pipe which stays toilet side of the low point and bubbles back through the joker valve which needs replacing.

Does this make any sense or have I missed something?

Thanks
Dave

[TravellingKiwis]

Attachment didn't seem to work, not sure why it is automatically turning it upside down though!!!

[peghall]

I'm guessing that sea water mineral and urine crystal buildup in that toilet's discharge line has built up enough to reduce the diameter enough to restrict flow, creating enough back pressure to cause the bubbling. (see attached photo for an example...those are 1.5" hoses) That it's happening in only one toilet indicates that toilet is the one used almost all the time.

Muriatic (hydrochloric) acid will clean it out of the hose. Use a 15% solution out of the bottle...flush it down the toilet...rinse after about 45 minutes. May require more than one application. Be sure to CAREFULLY follow all directions for safe handling!!

[a64pilot]

Originally Posted by TravellingKiwis

So ... my naive first time troubleshooting of a marine toilet and my hypothesis is that the toilet pumps some air into the pipe which stays toilet side of the low point and bubbles back through the joker valve which needs replacing.



Does this make any sense or have I missed something?



Dave

That is exactly what happens when my joker valve needs replacing, bubbling back, but also the water will slowly drain out of the bowl leaving the bowl empty. I’m sure my electric head blows air into the line.
In fact mine is doing it now, my first joker valve lasted two years, this one, one year, we are full time and only use the one head.
I think it’s possible that I over tightened the fitting that holds my Joker valve when I replaced it, and that may explain the early failure.

[TravellingKiwis]

Thank you both for your replies, much appreciated. The hose definitely had a very thin (0.5mm) lining of minerals etc at the end I could see and it is possibly this is thicker at other points so I will definitely get hold of some of the recommended acid for now and the future.

I am also in about to order a bunch of pump spares just in case I do need to change the joker valve.

Thanks again,

Dave

[a64pilot]

If you do the acid flush, be sure to not put it in an aluminum tank.
I know aluminum tanks are stupid, but some are out there. My boat had one.
I think I would have the valve open and direct discharge