Head Always Full

Jun 13, 2021
3
Catalina 320 Long Beach
So I have an issue with the head being full when it truly is not. We will suck out the tank to empty and then the head is full the next day. It is full to the extent that the bowl fills up. I thought perhaps the system was filling with sea water but I tested that by not using it 2 days and sucking it out and it was still empty. I think there is a clog in one of the lines, that's the only thing I can think of. Any experience on this issue?
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
When you say the head is full, do you mean the holding tank, or the toilet, maybe?
 

Joe

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Jun 1, 2004
7,999
Catalina 27 Mission Bay, San Diego
Are you flipping the flush/dry valve? Did you check the Y valve.
 

RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
Sounds like a worn out joker to me. Replace every Spring is a good idea.
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
So I have an issue with the head being full when it truly is not..............
Some possible causes:

1. Heads flushed with salt water accumulate scale deposits in the discharge channels and hoses. Scale deposits cause a head to get progressively harder to flush, and it is scale on the valves that allows water in the discharge line to leak back into the bowl. Calcium deposits eventually lead to total blockage, a most unpleasant prospect. Avoid this problem by running a pint of white vinegar through the head once a month.

2. Plugged sanitation hose. Solution is to auger it with an auger attached to a drill.

3. Fouled sanitation hose. Time to replace the hose.

4. Poorly lubed joker valve: Avoid this by pouring a 1/4 cup of vegetable oil into the toilet once a month.

5. If you’ve got the inlet selector switch set to “Dry” flush but water is coming into the bowl, consider a rebuild, as this problem can almost always be blamed on a faulty “Wet Bowl/Dry Bowl” selector switch or worn flapper/ball valves in the inlet/outlet section of the head Joker valve failure. Time to rebuild the head.
 
Last edited:
Dec 2, 1997
8,710
- - LIttle Rock
So I have an issue with the head being full when it truly is not. We will suck out the tank to empty and then the head is full the next day. It is full to the extent that the bowl fills up
I strongly suspect it's the other way around...water is filling the bowl via the toilet intake and FORTUNATELY is going into the tank and--also fortunately!-- is overflowing out the tank vent line when the tank is full instead of staying in the bowl to overflow it. This will happen if there is no vented loop in the toilet intake and the toilet is left in the "flush" or "wet" mode. I'd bet $1 that it was in the dry mode when it didn't fill up.

If I'm right, the cure is a vented loop in the toilet intake. It should be installed between the pump and the bowl and must be at least 6-8" above water line AT ANY ANGLE OF HEEL , not just when the boat is at rest...which on most sailboats puts it 2-3 FEET above the bowl. This requires replacing the short piece of hose the toilet mfr uses to connect the pump to the back of the bowl with two pieces of hose long enough to reach to and from the loop (see figure 1 on page 3 of the Jabsco manual toilet instructions Jabsco Twist 'n' Lock Manual Toilets (all manual toilet instructions show the vented loop in the same place). You'll use 3/4" sanitation hose (NEVER clear water hose...it's not rated for below waterline connection)...the least expensive flexible PVC #148 is fine for this.

The vented loop serves two purposes: 1. It creates a "hill" in the toilet intake line that's higher than water just seeking its own level can rise over...and 2. it breaks the siphon started by pumping the toilet. And btw, if you go exploring in the manual and see figure 3, a vented loop is NOT needed in the toilet DISHARGE line if it ONLY flushes into a tank. In fact there's even a better way to run that line than the manual shows.

Any questions, Louie? I'll be glad to answer 'em!

_-Peggie
 
Last edited:
Dec 2, 1997
8,710
- - LIttle Rock
And now for the rest of you.... Joe is the only one who's on the right track, the rest of you weren't even close and even offered some very bad advice!

Sounds like a worn out joker to me. Replace every Spring is a good idea.
Why do so many people think the joker valve is source/cure for ANY toilet problem, even in the toilet INTAKE ?? The joker valve should be replaced at least annually, but that won't solve this problem.

Some possible causes:

1. Heads flushed with salt water accumulate scale deposits in the discharge channels and hoses. Scale deposits cause a head to get progressively harder to flush, and it is scale on the valves that allows water in the discharge line to leak back into the bowl. Calcium deposits eventually lead to total blockage, a most unpleasant prospect. Avoid this problem by running a pint of white vinegar through the head once a month.
2. Plugged sanitation hose. Solution is to auger it with an auger attached to a drill.
3. Fouled sanitation hose. Time to replace the hose.
4. Poorly lubed joker valve: Avoid this by pouring a 1/4 cup of vegetable oil into the toilet once a month.
5. Joker valve failure. Time to replace the joker valve.
1. 90% of a whole pint of vinegar will just run all the way through the system into the holding tank. A cupful once a week will accomplish just as much without wasting good vinegar. It should rinsed out of the system with clean FRESH water after 45-60 minutes. Never leave vinegar sitting in the bowl...when soft rubber (joker valves) are left to sit and soak in vinegar, they swell and distort.

2. Don't even THINK of doing that! The right solution is a 15% solution of muriatic acid--available from any hardware store. If the hose is completely blocked, use just a cupful for the first application...it may sit in the bowl till it "eats" through the top layer. Whether it's completely blocked, it may require more than one application.

3. Unless "fouled" means "stinking" and/or the hoses are more than 5 years, replacing 'em shouldn't be necessary.

4. Joker valves don't require any lubrication...manual toilet pumps do. But a 1/4 cup accomplishes no more than a tablespoon...the excess just washes out with the first flush.

5. One more person who pins every problem on the joker valve. <sigh>
Joker valves don't fail, but they do wear out and should be replaced at least annually.

At least some of you have my book, but you make it obvious you've never even opened it! Try doing that sometime...you might learn something!

--Peggie
 
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Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
4. Joker valves don't require any lubrication...manual toilet pumps do. But a 1/4 cup accomplishes no more than a tablespoon...the excess just washes out with the first flush.
@Peggie Hall HeadMistress , would not the vegetable oil establish a film over the contents of the tank and impede, if not outright put a stop to any oxygenation ? Any aerobic action would then be slim to nil.
 
Dec 2, 1997
8,710
- - LIttle Rock
You'd think it would, and so did I for years, but people have been flushing veggie oil for decades without a problem. How that got started is interesting (at least I think so): The first piston/cylinder toilets were the bronze "thrones"--W-C Skipper, Imperial, Winner etc. Everything in 'em that's now rubber, neoprene etc was and still is leather, which absorbs oil. Instructions called for about 2 tablespoons of mineral or veggie oil every six months or so when the toilet could sit and absorb it at least overnight. As new toilet mfrs began to introduce simpler toilets with rubber and neoprene pump "innards" they continued telling owners use veggie oil even though rubber and neoprene don't absorb oil.

--Peggie
 
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Likes: Ward H
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
You'd think it would, and so did I for years, but people have been flushing veggie oil for decades without a problem.
I have to wonder if they even knew they had a problem. Of the many people I meet in boating today, I don't know if anyone has a clue about aerobic vs. anaerobic digestion in a holding tank. "C'mon, look what you're putting in there. It's gotta smell bad so learn to live with it :facepalm: "

Simply put, your head may have an H2S smell to it but you can make it even worse by covering the ingredients with oil.
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
Is it possible that the tank vent is plugged, preventing the pump out from really pumping the tank empty?
 
Dec 2, 1997
8,710
- - LIttle Rock
Is it possible that the tank vent is plugged, preventing the pump out from really pumping the tank empty?
Although his description of what's happening doesn't indicate a blocked tank vent, that's definitely worth checking. And it brings up one question I forgot to ask him: Is the water in the bowl clean or dirty? I based my entire "diagnosis" on the premise that it's clean...it may not be.

Good catch, David!

--Peggie
 
Jan 7, 2011
4,727
Oday 322 East Chicago, IN
Is it possible that the tank vent is plugged, preventing the pump out from really pumping the tank empty?
That was my first thought….vent plugged, pumped until it could not overcome the vacuum, stopped well before tank was emptied.

But on second read, the bowl is filling up…so not sure what would cause that…unless it was siphoning water.

Greg
 
Dec 2, 1997
8,710
- - LIttle Rock
It's not necessarily siphoning, Greg...water outside the boat is doing what water does: seeking its own level. And without a vented loop in the intake, it's succeeding in finding its own level in the toilet bowl. And it's only thanks to what has to be a worn and leaking joker valve that the water is going to the tank instead of overflowing the bowl.

At least, without any evidence that supports a better idea, that's my diagnosis.

Loved your book, btw!

--Peggie
 
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