Head filling with seawater

[YVRguy]

Hi folks. I have a different twist to a common problem. Every time I pump out the head when I return a while later it has filled with seawater. Now, I know that if the bowl fills with smelly water it means the joker valve likely needs to be replaced or it is some other problem on the holding tank side of the system. But in my case I'm quite sure it is fresh seawater coming in. This seems to happen regardless of which way the selector switch is positioned. Any ideas?

 

[Steve Dion]

Are your thru hulls closed? Do you have an anti -syphon on the raw water intake?

 

[YVRguy]

Are your thru hulls closed? Do you have an anti -syphon on the raw water intake?

The thru hull isn't closed but that has never been a problem before. I generally close it when off the boat for a while or in rough water but otherwise I leave it open so we can easily use the head. I am only just now reading about the anti-syphon valve you are referring to. I'm not sure that we have one. Perhaps that is the issue.

 

[Ralph Johnstone]

I am only just now reading about the anti-syphon valve you are referring to. I'm not sure that we have one.

My vote goes for the plugged (or non existant) anti-siphon.

Any chance you can run a clear plasic vinyl tube from another raw water source (something around the engine) to check the exact sea water level relative to your head ? If the rim of the bowl is below the water line .............. .

I'd keep the thru hull closed until you've corrected the problem with the anti-siphon.

 

[Rob2435]

I've had a similar problem on my 352. When a few people stopped by and we were all in the cockpit, the bowl actually overflowed. I have to check for an anti-siphon...Wouldn't they have installed one if the bowl is below or at the water line?

 

[kloudie1]

Doug, the valves in the top of the head that control wet and dry are leaking. If you close the thru hull and very carefully remove the top of the pump, you'll probably find some debris in the weighted flappers. Another problem is that the "switch to dry" cam is a little loose and not fully closing the valve. Depending on how much you use the head, the flapper valves and gaskets should be replaced every few years to keep it working .. An anti-siphon is recommended between the pump and the bowl, but the real problem is a leaking flush valve. Mine has done that a few times and I have always found stuff in the valves.. stuff like seaweed parts, seeds, bits of string, very small snails..

 

[Joe]

get a rebuild kit for the head pump assembly from the manufacturer, and also replace the joker valve while you're at itc. If you have an anti siphon loop between the pump and bowl you'll only get the small amount in the bowl side of the line... if you don't have the loop.. time to install one.

 

[Claude L.-Auger]

Doug, Kloudie is right on. The top of the bowl on my 34 is 2" below water line. There are no anti-siphon installed in the intake. The wet & dry valve of the pump quite often gets left partially on the wet side because of debris or guest poor operation. The incoming flow is real slow but it will overfill the bowl, which could sink the boat.

 

[Paul F]

Had the same problem years ago. The simple fix is to put a anti-siphon valve between the pump and the head. Here is a picture of the set up.

 

[centerline]

a working anti siphon valve is the proper fix...
the pump valves may also be worn and need to be replaced. and these valves can prevent unwanted siphoning.... until they dont anymore, or the lever is left in the wrong position.
but if it has a working anti-siphon valve you will have no worries about sinking because of the seawater inlet siphoning into the toilet....

and even for heads that are above the water line, when heeling while sailing, the head can then be below the waterline, in which case it can create a siphon.... and anti siphon valve located above the waterline no matter what position the boat is in, will prevent any problems with head flooding from the water inlet.. unless it clogs, which is rare.