Head filling question

[Doug]

Have a question about my head:

I have a Groco HF in Noeta. It fills when the through hull is left on.

I've rebuilt the head. Also installed new hoses and an anti-siphon valve. The system is set up: Through hull intake to pump to Siphon valve to bowl. The siphon loop is near the top of the Hanging locker next to the head.

Still, the bowl fills if the switch is left in the flush position. I thought a an anti siphon valve would stop that.

What am I missing here?

[Ray & Sandy Erps]

Maybe the anti-syphon valve is plugged so it can't do it's job?

[sail4dale]

had the same problem on my Cat30.  What I found there was the rubber flapper inside the pump assembly was shot and limed up.  I rebuilt the unit and it solved the problem for me.  Hope that is a solution for you.

[Ron Hill]

Doug : Check the valve as others have mentioned.  Also make sure that the valve isn't in there upside down (small flapper should be down)and the nut is only finger tight.   

[Ray & Sandy Erps]

One other possibility;  if you're going directly overboard instead of into a tank, the outlet line needs an anti-syphon valve too.

[David Sanner]

Doug,

Maybe I'm missing something but aren't anti-syphon valves are for
pressure lines not suction, in fact that's what they stop, the suction
from the lower side of the line causing a syphon.

I guess you could have one on the intake but when you pumped water
in it would suck some air in as well.

The 1988 model has one seacock for the head intake (direct, no anti-syphon) and
the pump out for the shower which does go through an anti-syphon valve.

Consequently if I leave the head on 'wet' it will slowly overflow the bowl.
Not the best design it seems.   I know some on this board have even
connected the starboard fresh water tank to solve that and other problems.

[Doug]

David,

The vent loop is between the pump and the bowl, not between the pump and the through hull intake. 

I put it in to stop the slow fill you described, but no luck so far.

Been in touch with Peggy Hall. She thinks that the valve may too low. I'm going to move it as high as I can and see what happens.

[David Sanner]

Doug,

That makes sense... if you can get that to work I'll put that on my list!

I don't see why it wouldn't unless it was too low or the valve was stuck/broken.

Good luck.   

[Susan Ray]

I agree witth David that the anti syphon valve is not same as a back flow valve. A back flow valve in the intake liine should work no matter where in the line it's installed. Is the head filling from the intake or the pump out?  If it's filling from the discharge, do you have a loop, extending above the water line, in the line from the discharge at head to the thru hull (or holding tank) ?

[Footloose]

David,

I just finished this upgrade also although I haven't spashed the boat yet.  I measured the height of the anti siphon valve under the head sink from the floor.  I also mounted the anti siphon valve in the locker next to the head.  I put it as far up as was practical which put it 2-3 inches higher than the other one.  I don't remember this being mentioned in this thread, but the valve has to be above the water line even when heeled.

Hope this helps.

Dave

[Doug]

Changed a few things (raised the vent a bit) and it still does not work.

The bowl is roughly at the water line, and the loop/ vent is 20" above that. Still floods.

I've tried removing the valve entirely and creating a hole in the loop after flushing and it still siphons. Also tried it with the through hull outlet closed to make sure it wasn't coming in that way.

The waste line had a pre- existing loop in the same area. Now I'm thinking if the water loop doesn't work the waste vent won't work either.

Both of these loops are in the hanging locker. I'm not inclined to install the hose/ loop anywhere else because it would become visible in the cabin or head.

My biggest concern with the flooding was when there are guests on board for the night.  I didn't want them having to go into the tangle of hoses and valves under the head to figure out which water valve to turn on to flush. Also don't like the idea of turning a through hull off and on all day.

At this point I think I may abandon the loop and all vent all together and install a manual valve right behind the hand pump. That way we can leave the through hull on and turn the water on & off at the head. Not perfect, but gives me a easy to use and clearly visible defense against flooding.

[David Sanner]

Doug, sounds like you must have a problem with your valve.

If you think about it, if the valve is working correctly it's like cutting
your hose there and having the two ends facing up.   The water on
the seacock side should simply lower to the waterline.

Or, now that I think about it  ... more likely the head pump is leaking
into the bowl as it's not protected by the anti-syphon valve.

To make sure you could remove the anti-syphon valve and just have
a hose standing there (above the water line).  Without using your
head see if it floods.   If it doesn't then it's the valve, if it does
maybe rebuilding your head (like sail4dale did) would do the trick.

[Ron Hill]

Doug : I've got my vented loop between the thru hull and the pump on the suction side.  Did that because one spring I was cleaning behind the head and the fill line literally fell off of the pump housing!!  The plastic inlet to the pump cracked off!!!  But then that's another story which I've already passed on.

If you loop is mounted as high as the 2 others under the head sink, I think that you should contact the manufacturer of your  vented loop and ask them for another valve.   

[David Sanner]

Ron,

So... I'm assuming that works for you.  Does the vent suck much air?  After
pumping does an air 'pocket' eventually form at the top of the loop which
must be drawn through as you pump.    Any problems with your setup?

I'm figuring it's only a matter of time until my head overflow because someone
leaves it on wet or a worse case scenario the hose fitting has issues like you had
so maybe I should move this up on my list.

In my boat (1988) there are three thru-hulls under the head sink: engine, sink, and
a shared shower pump (which is the only vented hose) and the head inlet are teed
together at the stopcock.  Could the head and shower share the same vent?

If so, things would be hooked up in this order:
Thru-hull, vented loop, then a tee which one hose goes to the shower pump the other to the head.
As long as the head didn't draw too much water/air through the shower pump instead
of the thru-hull that seems like it might work.  (Or the shower pump) ...
Ok maybe I need two vents (or a check valve) but it would be nice to just move
the T instead of buying another $30+ vented loop and misc parts that add up.

If this did work, in case the shower pump failed, you could just
close the seacock and pump the shower out via the head.

One way to find out for sure...

So you have three vented loops under the head sink?

[dave davis]

One more reply from a new Dave.
I also have a 1988 and it has a Jabsco manual head. The first thing I would check after hearing all the work you have done, is replace the JOKOR valve which is the 1 1/2 inch valve on the outlet side. They get very bad and need replacement. Part # 29092-00 cost 10.99 at WM.
A new Jabsco head cost $150, but I can not remember if they come with a JOKOR valve.
Dave D.