Toilet won't hold water

[nph]

I have a Jabsco eletric head. It has three buttons to work it, A push button to flus, then to rocker switches, one to fill and one to drain the bowl.

If you fill the bowl or flush it, about 10 seconds later, the bowl empties on its own.

How do I correct this?

Thanks
Scott

 

[Vic Willman]

Marine toilets are built for a whole host of onboard applications. The toilet itself, in most cases, DOES NOT hold water in the bowl between flushes like a toilet at home does. Holding water in the bowl between flushes is a function of the external plumbing. What needs to be done, is that the discharge hose (larger hose) needs to be routed UPWARD, higher than the top of the bowl, to a vented loop fitting, than back down to the holding tank, treatment system, or other ultimate destination. The vented loop fitting is an anti-siphon device, that will keep the water from leaving the bowl between flushes.

Owners who have boats that serve more as a summer home, and rarely leave the dock do want the toilet bowl to retain water. But others who have sport fishermen, as an example, and will be banging around out in the waves - they don't want the water sloshing out of the bowl onto the teak parquet flooring in the head. So, in order to meet all the various applications and requirements, toilets directly from the manufacturer do not normally retain water in the bowl. But if you wish it to do so, it can be done by re-routing the plumbing and adding the vented loop fitting.

In the case of the Raritan "Atlantes" series toilets, they can be special-ordered with an internal vented loop fitting already built into the head, that will keep water in the bowl between flushes. It's an-extra cost option that is quite popular with houseboaters.

 

[Selby]

Any diagrams or parts list available for such a thing? If the toilet is dry wouldn't that allow the smell from the holding tank to get into the cabin?

 

[Radioactive]

"If the toilet is dry wouldn't that allow the smell from the holding tank to get into the cabin?"

It shouldn't.

In a home system, there is an S-shaped trap which holds the water and the water forms a vapor seal.

In a marine head, there is ( In most systems ) a "duckbill valve" or flapper which acts as a one-way valve. This prevents material on the waste side form returning into the bowl side. The water trap is not required and in some cases, not desired.

 

[nph]

Vic,

That makes sense to me, I will have to check out the waste hose on mine to see how it is routed. I understand the need to retain the water vs, the need to empty the bowl, I thought thats what the rocker switch did, give you the best of both worlds.

I just thought that the bowl would hold the water long enough do to finish business, before flushing. I also thought that the vented loop, was only needed when the over board discharge was below the water line, to prevent flooding the boat thru the toilet.

I know there are an awful lot of "I thoughts" in there it just shows I have a lot to learn. I do like to know how and why each system on my boat works, this way then there is a problem I stand a chance on fixing it.

My last boat had a port-a-pottie. It was a lot a simpler, but no where near as useful!

Thanks for your help.
Scott

 

[JoeBTB]

Vic, thanks for that information. Can you clarify one more thing? I have a manual head, with a vented loop as you describe. When I flush, should I be able to pump everything up over that loop? How much water intake does that require, or can that be done while flushing dry?

Usually what I do is flush with water for about 5 strokes, then about a dozen strokes dry. There's nothing in the bowl at that point, but after being under way for a while, some water usually makes it back to the bowl.

 

[Vic Willman]

Basically Joe, it depends on the toilet and how far it moves the effluent per stroke. This is basically determined by the toilet's cubic inch displacement. Area of the piston X length of stroke, minus maybe 10% for inefficiency.

Don't put too much reliance on how far the toilet will pump in the dry flush mode. The purpose of the dry flush mode is to pump out without bringing in any water. If the toilet is new or has had a recent rebuild, chances are it'll pump at least 6 feet in a straight line, provided that 6 feet isn't up, over a loop. But as the internal parts of the toilet wear, the toilet's pump becomes less efficient, and it won't pump as far.

With a Raritan PHII, it will move the waste aproximately 12" through the lines per stroke - most other manual toilets only have about half the displacement, so will only push it about 6" per stroke.

If you're getting backflow into the toilet bowl between flushes, it's time to replace the joker (duckbill) valve in the toilet.