jabsco head filling with water

[schoonerdog]

I've got two newish heads (both installed less than a year) and they will occasionally completely fill with water. We're a catamaran, so the rim of our head is actually above the water line, so it didn't turn drastic. And putting a bit of head lube will tend to fix the problem (at least temporarily), but I never know when it will happen again. What's the valve responsible for this? Other than shutting off the through-hulls everytime we leave, any other solution or thing that will help? We're a live-aboard boat and so these heads tend to be used much more than a normal head would. I don't think the head needs to be rebuilt after 6 months of use...as a followup question, are there any types of heads which would be more resistant to this issue?

[Vasco]

Again the flapper valve unit. See my answer to sneuman. Are you switching the little lever to "dry"?

[S/V Illusion]

Once again, before you start playing with the joker valve, start with the obvious and simple and most likely cause as described below by Peggie in a recent response to a similar problem on another forum:

"When the vent is blocked, air in the tank displaced by incoming waste has nowher [sp] to go, so pumping the toilet pressurizes the tank, pushing waste back toward the toilet. Ignored long enough, it can pressurize the tank enough to burst it.

All of the above assumes that what's filling your bowl IS waste water backflow. If it's clean water, it's coming in via the head intake. If it's happening when the toilet is in the dry mode, the wet/dry valve has failed. If there's no vented loop in the head intake, it's allowing water to rise in bowl to the boat's waterline. To fix that, you need to install a vented loop in the intake (it goes between the pump and the bowl, btw), and either replace the wet/dry cam assembly, or better yet, the whole toilet."

[Vasco]

If the joker valve goes you'll get backfill from the holding tank.

[schoonerdog]

OK, let me see if I got this right then. The water is clear, definitely coming from the outside, and always when the pump is on dry. It's happening on two new heads and after using a bit of head lube seems to go away. So I'm guessing that the wet dry valve is failing. I don't think it has a vented loop however, is the vented loop always necessary?

[S/V Illusion]

Originally Posted by schoonerdog

I don't think it has a vented loop however, is the vented loop always necessary?

If the head is below the WL, your insurance company would prefer it.

[S/V Elusive]

To add a bit to Illusion's quip; ANYTIME that your head is below the waterline (think heeled over) they, and probably you, would prefer there is a vented loop!

[JusDreaming]

but to answer your question, no catamarans very seldom have vent loops. And the key answer is rather the water is waste or salty, if you must you could taste it :O. But the thread "Vasco" steared you to, has an e-mail for customer service for jabsco, for replacement of a faulty part!!

[S/V Elusive]

Oh damn .. I missed completely that it was a catamaran - when you heel one of those puppies, you got other problems than a vented loop.

[JusDreaming]

Originally Posted by S/V Elusive

Oh damn .. I missed completely that it was a catamaran - when you heel one of those puppies, you got other problems than a vented loop.

the crappy smell will not be from the holding tanks

[Joli]

The line may still be siphoning even though the toilet is not below the waterline. The simple fix is to intall a vented loop on the intake and discharge sides. Lord knows I stole enough gas as a kid with that trick :0

[44'cruisingcat]

Originally Posted by Joli

The line may still be siphoning even though the toilet is not below the waterline. The simple fix is to intall a vented loop on the intake and discharge sides. Lord knows I stole enough gas as a kid with that trick :0

Yes, the toilet will still fill to the outside water level. A syphon breaker should fix it.

[cal40john]

Originally Posted by 44'cruisingcat

Yes, the toilet will still fill to the outside water level. A syphon breaker should fix it.

Originally Posted by Joli

The line may still be siphoning even though the toilet is not below the waterline. The simple fix is to intall a vented loop on the intake and discharge sides.

The bowl will fill to the outside waterline if the leak is from the exhaust side, and the exhaust is plumbed to a through hull below the waterline. Picture the end of the siphon tube being the hole in the bottom of the bowl.

The rim of the bowl is the end of the siphon tube on the intake side. If that (the rim) is above the waterline there is no siphon. If it is below the waterline, there is no reason for the siphon to stop until the boat sinks.

Schoonerdog, do you have a Y-valve on the exhaust side? Do you leave the seacock open on the exhaust? When you find the head with water in it, is that level even with the outside water level? Even if directed at the holding tank, Y-valves can leak from the supposedly blocked off side. This would also require that the valves in the head leak as well. This would give you clear water in the bowl, and it would only fill to the outside water level. A siphon break in the exhaust would allow you operate with less than perfect valves.

To answer your other question, look at Lavac heads. No valves except in the separate diaphragm pump.

John

[schoonerdog]

John, et al, thank you all for you information. I think I get it now. A stupid question before proceeding. Won't a siphon break in the exhaust side, well, stink?

[cal40john]

Originally Posted by schoonerdog

John, et al, thank you all for you information. I think I get it now. A stupid question before proceeding. Won't a siphon break in the exhaust side, well, stink?

Put a tube instead of a check valve at the top of the loop. Run the tube outside the boat up high.

John