Head Sea Water Shutoff Valve & Antisiphon question

[RV61]

 

Until recently we have been lucky that have not had any real issues with the head. After a couple overflows from the person using the head not putting the handle in the dry position we started using freshwater from the shower/sink facet in the head to flush the head and always keeping the handle on dry position. This method also made occasional odors go away. Recently I noticed after showering the head bowl had water in it and chalked it up to may not have close lid when showing until this weekend as the flush valve lever was in dry postion. The seacock that a sea water flush would come from is also set up as the sump drain for the shower and we would usually keep that Seacock closed unless we shower. The hose for the shower sump has a check valve . I had opened the seacock to prepare for shower and then got to doing something else and the next time I went in the head the bowl was just starting to overflow with sea water. Closed seacock and pumped dry. Opened seacock and the bowl started to fill. Three questions. From this I gather my Anti-siphon needs servicing or replaced?  By Putting a gate valve in on the water inlet hose to the head so that the only way sea water could enter the bowl is to open valve Thus eliminating issue if anti -siphon is bad  and forgetting to close seacock or if the lever was left in the wet postion?.  Should a properly working anti siphon eliminate bowl filling and overflow if  head lever left in the wet postion the bowl filling up?
I had read a couple earlier threads and back issues of tech notes thru a search of anti siphon but still have the above questions.

Thanks
Rick

[Peggie Hall]

". From this I gather my Anti-siphon needs servicing or replaced? "

I would say definitely yes!  That is, IF you actually have a properly installed vented loop in your toilet intake...which, from your description of your problem, I'm inclined to doubt.  Where is it--in the line between the thru-hull and the pump (wrong place!)?  Or between the pump and the bowl  as shown in the installation installation instructions for every manual toilet (right place)?  How high is it?  It SHOULD be at least 6-8" above waterline AT ANY ANGLE OF HEEL...which, on most sailboats, puts it at least 3' above the toilet.

The shower sump should NOT drain via the head intake thru-hull!  All the hair, soap scum etc in shower water causes all kinds of problems in the toilet pump...and I guarantee you Catalina didn't do that!   Where in the head intake line does the shower sump drain line tee into it?  I'd bet real money that it's between any vented loop (that's in the wrong place anyway) and the toilet.

The shower sump should either have its own thru-hull or share the head sink drain thru-hull.

"Should a properly working anti siphon eliminate bowl filling and overflow if  head lever left in the wet postion the bowl filling up?"

Yes...that is, provided it's correctly installed. If the system is plumbed correctly, you neither need nor want any gate valves or check valves.

If you'd like to email me, I'll help you sort out how to replumb everything the way it needs to be to work the way everything should.   

[RV61]

Peggy,
Thanks for the response. I tried to email but your e-mail address is hidden in your Catalina 34 website profile. Let me try to set out the plumbing arrangement. Under the sink vanity. I have three seacocks. One is dedicated for raw water engine cooling. 2nd is currently the sink drain only. The the third is set up as the inlet for water to the head and the shower drain . Believe it our not this is how Catalina set the boat up. See drawing on page thirty 38 of the MK1 model manual found under manuals from home page of the C 34 website. Please take a look. As you will see from the seacock for head inlet hose goes directly to the head and this line is not vented there. The shower drain starting at same seacock goes to the Anti-Siphon then the diaphram bilge pump then to the shower drain otherwise stated when showering the water goes from the shower drain to hose Thur a check valve to the diaphram bilge pump up thru the anti siphon and out the seacock. Note have never had an issue with the shower debris soap hair etc going to the head. Notes This is a manual head and the shower drain appears to be  further below the waterline than the  seacock. When you say  the vent should be  - between the pump and the bowl-
are you referring to the head pump? 

From your comments the best set up would be.?
To eliminate the water in the bowl when lever is left on wet by mistake properly installed and functioning second anti siphon between the manual hand pump on the head and the bowl with teeing it the the sink drain? Thus the current  this seacock would handle sink drain and head intake.  Why a difference in using shower drain seacock vs sink drain seacock as as head water inlet? Both have debris shaving cream  tooth paste and whiskers vs hair and shampoo. To eliminate and other issues need to install or fix existing antisiphon as well to prevent any siphoning back up thru to shower drain? Would a better fix be having the sink drain and the shower sump drain be on the same sea cock and have a dedicated inlet? 

Your input is very much appreciated

Thanks again.
Rick 



   

[Ron Hill]

Rick : The answer is that the anti syphon (vented loop) is for the shower discharge line.
 
The problem is that the head intake raw water line is also connected to the shower discharge - same thru hull.  If you look at the outside hull water line you'll find that the bottom of the head bowl and the thru hull are both below the water line!!!  That's why the factory put the sticker on the head sink door that says something like -- "IMPORTANT IMPORTANT !!! CLOSE THE THRU HULL EACH TIME AFTER USING THE HEAD!!"

What's happening is that the outside water can and is syphoning in to the head when you open the thru hull.  If you have the head pump lever in DRY BOWL and the water still syphons, I'll bet you have a problem with a bad top gasket on the head pump assembly and need a new gasket - so the dry bowl works properly.  

Your idea of another cut off valve on that head water intake line is OK, but I'd use a ball rather than a gate valve.

I'm sure that the maker of your head has a diagram of how to add a vented loop to your intake line.  That would also solve your problem.

I have my own fix for that problem, but it's too controversial to bring up!!    A few thoughts  

[Peggie Hall]

Rick...you can email me at (my.name)(at)gmail(dot)com  Be careful how you spell my name.

Ron said...
"What's happening is that the outside water can and is syphoning in to the head when you open the thru hull."

He did get that part right...that's exactly what's happening. However, the top gasket in the toilet, good or bad, isn't your problem. What IS needed is a properly installed vented loop in the head intake.  A shutoff valve isn't needed or recommended.

Catalina really did plumb it that way???  Wow!  Otoh, they are the same folks who insist on running vent lines into rail stanchions...so I guess nobody's perfect.

[Stu Jackson]

And switching the head sink drain line from it's own thru hull with the shower pump outlet will allow you to use fresh water for the last flush of the day from the head sink.

No additional T is required.

An unforeseen consequence, but in this case, a good one.

From here: reply #16  http://c34.org/bbs/index.php/topic,5755.msg36265.html#msg36265

[Ron Hill]

Rick : Follow Peggie's suggestion and install a vented loop for your head.  The problem that you'll probably run in to, is that most (Jabsco at least) has the vented loop in the line between the pump and the bowl.  There is no syphon protection for the line from the thru hull to the pump!!! 

You still need to change out the gasket/valve assembly on the top of the head pump - so dry bowl/wet bowl works as it should !! 

[Stu Jackson]

There is no syphon protection for the line from the thru hull to the pump!!! 

And there shouldn't be, 'cuz the head won't work.

[Peggie Hall]

"There is no syphon protection for the line from the thru hull to the pump!!! "

Of course there isn't...because that's not where it belongs.  A siphon break between the thru-hull and the pump would cause the pump to pull in air, preventing it from priming.  That's why it has to be between the pump and the bowl...because the pump PULLS water from the thru-hull TO the pump...but PUSHES it from the pump the bowl...and a siphon break can't interfere with water being pushed through a line.

Stick with me, Ron...and I'll show you things you never imagined!   

[RV61]

All,
First thanks for all the posts on this topic. Finally getting around to fixing the issue. My current Groco HF in addition to a worn gaskets and wearing Joker valve the head has a small crack in the china so it is time to replace. Wanted to let you know after speaking to Groco the following:

Water coming into the bowl in the dry position is due most likely to worn gasket or faulty spring or both as Ron mentioned. They recommend putting the antisiphon between the bowl and the holding tank however some put between the head pump and the bowl.

Ron thanks for explaining current antisiphon is for the shower sump discharge line a not the head even though on the dame sea cock.

Stu I like your setup of same seacock for head sink drain and head as we have been using fresh water to flush and I saw no need to plug sink if need to use sea water. Nice!! Groco mentioned many do this.

For any one with a Groco HF and is thinking of replacing with same be aware that Groco did change the foot print about two years ago. The screws that bolt to the floor and 2 of the four screws are now 2.5 inches starboard for more stability.
Thanks again!!
Rick
     

[tonywright]

Rick: you should read Peggie's last post on this topic: http://c34.org/bbs/index.php/topic,6261.0.html.

Tony

[Peggie Hall]

Rick, you misunderstood this part:

Water coming into the bowl in the dry position is due most likely to worn gasket or faulty spring or both as Ron mentioned.

Water cannot get into the bowl unless the water is in a line connected connected to the bowl. So SOMETHING is happening at the thru-hull that allows water into the head intake line.

They recommend putting the antisiphon between the bowl and the holding tank...

How would a vented loop (antisiphon device) in the toilet's DISCHARGE line prevent sea water from getting into the bowl via the head intake line?    A loop--just a loop, not a vented loop because no siphon could get started in that line that can't be broken by simply letting out the sheet to right the boat--can prevent backflow from the tank  that spills into the head discharge line when the boat is heeled from getting back to the toilet.

...however some put between the head pump and the bowl.

"Some??"  A vented loop is ESSENTIAL in the intake--and it MUST be installed between the pump and the bowl, not between the thru-hull and the pump--in any installation in which the toilet is at or below waterline.  But a VENTED loop would be recommended in the toilet DISCHARGE line ONLY if the toilet flushes directly overboard.  Without one, sea water CAN flood the bowl if the discharge seacock is open while underway.

However, vented loops only do two things...1. create an arch high enough above the waterline to prevent water from outside the boat from getting over it while the boat is at rest...and 2. break a siphon.  Siphons can only be started by PULLING water through a line...which is what priming a pump does.  Pushing water through a line will not start a siphon.  So a vented loop  CANNOT prevent an effect known as "ram water"--sea water PUSHED ("rammed") up a hose through an open seacock--from flooding and even overflowing the bowl. So the air valve in your vented loop may be just fine. Otoh, if some misguided soul put a vent LINE on the nipple instead of an air VALVE in the hole in the nipple, it does need repair...that vent line needs to come out! 'Cuz the diameter of that hose is so small that it only takes about a week for salt and sea water minerals to clog it up...turning a vented loop into an UNvented loop that no longer has any ability to break a siphon.

Bottom line: No matter what else may be causing your toilet bowl to take on water,  it couldn't happen unless water is getting into the head intake line through an open or leaking seacock and then being pulled over the top of the loop. Replacing gaskets and springs may keep it out of the bowl, but that won't keep it out of the intake line. So you need to correct the problem at SOURCE of the water (the thru-hull) before it becomes a much bigger problem.

And btw..keeping the intake seacock closed all the time and flushing only by pouring water into the bowl is VERY bad for the pump because bowl contents only go through the bottom part of the pump...leaving the top half of the pump dry all the time, which wears out the rubber parts a lot faster.  Replumb it to tee it into the sink drain line and operate your toilet as it was designed to be operated.

search tag:  pouring bowl

[Ralph Masters]

http://www.ittflowcontrol.com//files/29090_29120_toilets_0406_data_sheet.pdf

Go to this link to see how and where to install the anti siphon loop.

Ralph
Ciao Bella

[Peggie Hall]

And page 5 of these instructions: http://www.raritaneng.com/pdf_files/ph_II/L04v0505.pdf

Let's not leave out page 14 of these instructions http://www.thetford.com/LinkClick.aspx?fileticket=%2fCbPQcp3Ftk%3d&tabid=756&mid=1763