Vented Loop Valve OK on Toilet discharge?

[Bassman3]

Since I bought this boat my forward toilet will sometimes drain out the bowl water after a flush. The vented loop line is clear. Looking at the Raritan Atlantes manual, I believe the loop is not high enough and the discharge siphons out the residual water. On the other hand maybe it is a toilet problem?
Problem is, if I raise the loop to the level I think I need (6" above the toilet seat), the vent hose will run downhill which I presume will defeat its purpose. It will form its own loop and undoubtedly get some fluid in there and plug.
Would it be OK to install a valve on top of the raised loop and discard the vent hose? Any recommendations on type of valve. I suspect I will have to check and clean the valve periodically.

[peghall]

Which version of the Atlantes is the toilet? How old?
Does it flush only into a tank or does it also flush directly overboard? If both, does that happen only when flushing overboard?



--Peggie

[peghall]

One more thing (I waited too long to add this to my previous post): Do you have the owners manual for it?


--Peggie

[Bassman3]

It is an A5 Model and I presume the same age as the boat, 25 years. There is an old brochure in the boat files dated 1998 that shows my toilet so I assume the toilet is original.
It only flushes into the holding tank now. The plumbing was set up to pump overboard with a Y valve but I had that dismantled when new hoses were installed right after I bought the boat. I think the new discharge hoses were placed similarly to the original setup but I wasn't directly involved. Maybe the installers messed up.
I have an online manual for the A5 I downloaded. There is no original manual.
A diagram in the manual I have seems to indicate that the vented loop should be about 6" above the toilet seat. Mine is about 3" below the level of the toilet seat.
See figure #8 in attached manual .pdf

[Uncle Bob]

Hi, you say that the overboard discharge has been eliminated and the toilet only flushes to the holding tank, is the entry to the tank at the top where it should be? If so then you don't need a vented loop at all, a correctly installed vented tank will not syphon back to the toilet.

[Bassman3]

The plumbing is as you describe. To be clear though, the problem is not that discharge siphons back into the toilet from the tank. The flush water and discharge is all exiting the toilet leaving the toilet bowl empty after the flush. That does not seem right to be. Being electric, I have to pour water into the bowl before using it again.

[peghall]

Originally Posted by Bassman3

The plumbing is as you describe. To be clear though, the problem is not that discharge siphons back into the toilet from the tank. The flush water and discharge is all exiting the toilet leaving the toilet bowl empty after the flush. That does not seem right to be. Being electric, I have to pour water into the bowl before using it again.

Assuming that your toilet uses onboard pressurized fresh water, I THINK I know what your problem is: Flushing the toilet SHOULD bring water in...it seems to have stropped doing that, most likely to a failed/worn out solenoid valve in the intake line.

If your toilet is plumbed to use sea water, there has to be a remote intake pump that's no longer bringing in water. That may be due to a blocked intake thru-hull (seacock closed?) or blockage that's most likely animal or vegetable sea life that the pump has pulled in.

A new solenoid valve or remote intake pump should solve the problem.

In either case, the vented loop in the toilet discharge line has nothing to do with it, nor--as Uncle Bob said--is a vented loop needed in toilets that only flush into a tank.

I suggest you give Raritan tech support a call: 800-352-5630 Your toilet is old enough that Mac McCoy is the only one of their techs who's been there long enough to be totally familiar with it...his extension is 306.

--Peggie

[Bassman3]

Thanks Bob and Peggie for your input. But this just shows how hard it is to discuss such things in relatively short written back and forth submissions.
The water flow is fine. Lots of flush water comes into the toilet to flush when the button is pressed. I have the Atlantes to the high flow setting.
As the flush ends though, most, sometimes all, of the water gets sucked out leaving a dry bowl. It's nice to have some water remain in the bowl ready for its next use. So that is why I have been adding some manually.
It is like once the flow gets going, all the water and contents are siphoned out so that is why I am investigating the height and function of the vented loop and if I can get away with a valve on the vent rather than retaining the vent hose I currently have.
Maybe this is normal. If so, it means my other Atlantes toilet is not working right since it retains just an appropriate amount of water.
Although on that one, I get a little dirty flow back INTO the bowl sometimes. We covered that (to no success even with help from Mac McCoy) in a previous post a couple years ago.
I think it may be time for new toilets after 25 years!

[peghall]

I think it may be time for new toilets after 25 years!

I agree! The Atlantes Freedom is a major improvement over the original A5 and A6 versions. Raritan Atlantes Freedom This retailer has it for the best price
Boatersland Raritan Atlantes Freedom

However, after spending some time reading the manual, it appears that your toilet may be leaving the amount of water in the bowl it's supposed to. It's not being siphoned out, it's just draining. There's an internal vented loop that may just need a valve replacement.

Fwiw, marine toilets typically aren't designed to keep as much water in the bowl as "the one at home" because water can end up all over the head in rough seas or even a serious wake. As long as yours are leaving enough water in the bowl to prevent "skid marks" after solids, there may be nothing wrong with it. If your flush lever isn't too old to be a 3 option version, you should be able to use it to bring in your desired amount of water.


--Peggie

[Bassman3]

That internal loop sounds like it might be the problem.
I will focus on that for a while. It may be the issue with the second toilet too.
Many thanks Head Mistress!

[peghall]

Glad to help...You might consider talking to Mac again.


--Peggie

[Bassman3]

I've spent some time fussing over it during a pumpout today and I think a better description is "draining" rather than "siphoning". The flush water just leaks out at the end of he flush. I will contact Mac.
Thanks again.