Weird Electric Flush Behavior

[Shrew]

Our previous boats have used a manual flush head (Jabsco). Our 'new to us' boat has an electric flush. I believe there is something malfunctioning.

We have a holding tank and use Marine/RV chemicals. Normally we would pour in a bit more the prescribed amount into the bowl, then flush. This pushes water and holding tank chemicals back to the holding tank.

Like a residential toilet, the flush water enters the bowl from around the top of the bowl itself. This is also the case with both the old manual pump and the electric flush. Both the manual flush and the electric flush are using raw water.

I cannot wrap my head around why the incoming flush water, which should be raw water, is now blue once I add holding tank chemicals and flush. WTF???!!! I've never seen this with my old manual flush heads. This is only occuring on the electric flush. Unlike the old manual flush, which had a diaphram pump, it is my understanding that the electric is using an impellor.

How is water getting from the discharge line in the bowl, to the raw water fill line??

[Kenomac]

Wow, that's a puzzlement?

[Sailmonkey]

Bad seals between the raw water and discharge impellers.

[Shrew]

So, I'm just looping around on this one for some closure. The head is a Jabsco model 37010. I found a service kit for that model. That appeared to fix the problem. The service kit comes with a parts schematic which made it easy to follow. Once you get in there the separation of the impeller and macerator running off of the same spindle on a single motor make more sense.

I did end up needing to use a high tack gasket adhesive to hold the o-ring in place during reassembly. The o-ring in the service kit seemed just a hair large.

Thanks to those who replied.

[44'cruisingcat]

Originally Posted by Sailmonkey

Bad seals between the raw water and discharge impellers.

This.

[rossny]

Hi all, I also have a new to me electric head and some questions. The water level in the bowl varies by the flush and the flush water looks dirty sometimes. Not sure if this matters but the holding tank is a collapsible one,should I replace with a hard one?

[peghall]

Two most likely reasons:
USCG regs require that all waste tanks be vented to the outside of the boat. A blocked tank vent would cause the tank to become pressurized, creating back pressure that's causing tank contents to back up into the toilet.

If your tank is an UNVented tank, the same thing would happen. Installing the required vent line would solve the problem.