Head Question

[dkb498]

Hi All,

So I have read a number of posts on this board regarding Heads, vented loops, Joker valves, etc.

Based on those readings, I'm replacing our old Headmate head on our Islander 32 with a New Raritan PHC. Along with the new head I am adding a vented loop for my raw water intake but have a question regarding the holding tank side.

We are an inland lake boat so I have removed the "Y" valve to the overboard so our setup is from Head to holding tank, holding tank to deck pump out. It's about a 20-25 gallon tank.

We have had an issue with holding tank waste flowing back to the toilet under significant starboard heel. Is the joker valve supposed to prevent this back flow or is there an additional requirement for another vented loop? AKA - will the new Raritan head will solve this problem or will I still need a vented loop.

The Problem I may have if I still need a vented loop is that the holding tank is under the vee berth and under significant angles of heel I may or may not be able to get the loop all the way up above the water line. I'm Pretty sure it's above when sitting level.

Thanks for any Thoughts or suggestions.

DB

[Mycroft]

I'm not familiar with the Raritan head, (you may find the correct information in the manual), but if heeling causes the tank to be higher than the head, then yes, you should have a vented loop that is higher than both to prevent the back-flow. Or if there's already a loop, it's probably clogged.

[Mark Zarley]

The holding tank needs to be vented to the outside of the boat. A vented loop is not needed or desired as it would vent your holding tanks gases into your living space, but your tanks vent should go as high as possible, up to the bottom of the deck" then back down to the ""thru the hull" vent fitting with a reverse scoop on it. This loop will keep water when you are heeled from backflowing into your holding tank. The scoop will create a suction on the vent as water flows by. The joker valve is the check valve that prevents blackflow. The siphon break is for the raw water to the head. The common cause of sewage backflow is a worn, partially blocked or chemically distorted joker valve. Notice I said backflow, not talking blockage or venting issues. I used pvc pipe and ran my vent 5 ft above my pilot house, it looks like a shorty antenna. Got it away from the side of the boat where it created boat farts, even with a charcoal filter. Happy wife, happy Life.

[SVTatia]

My take is if you put a vented loop between head and holding tank you'll be sharing its odor...

The holding tank is vented outboard and should not need a vented loop between it and the head. If you have the room, run the hose from the head a foot above the waterline than down to the holding tank. The joker valve prevents flow back from what is left on the hose.

Edit: Mark - you beat me to it by minutes...

[sailorboy1]

My last boat had an electric head and raw water would fill the bowl. Couldn't put a vented loop between the inlet and the head as that would airbind the pump, so just installed a manual ball valve at the head.

There shouldn't be a vented loop between the head and the holding tank.

I also think you should rethink the discharge valve from the holding tank overboard. You are going to want that when outside the discharge limits.

[dkb498]

Thanks all,

Responses were very helpful.

There is a vent on the Tank that runs up to the Deck. Mark Zarley & Sailor Boy. We're inland lake, Land locked so there is no discharge limit...and the thru hull fitting capped off.

sounds like my issue was the joker valve on the old head.

[Mycroft]

Originally Posted by sailorboy1

There shouldn't be a vented loop between the head and the holding tank.

Guess mine is plumbed wrong. Oh well, not the worst thing.

[a64pilot]

OK, first the inlet of the holding tank should be at the top of the tank, so that unless it's completely full, you can't get any back flow from the tank?
If so the back flow is coming from the hose, I had a similar issue and on mine it was the tank vent was completely blocked with a dirt dobber nest, so when I pumped into the tank it was under a slight amount of pressure, enough that it would cause a little backflow back into the head, unclogging the vent solved the issue

[Stu Jackson]

You might want to simply read the instructions that come with the PHC. Lots of stuff in these replies is good, some is plain wrong. You can get them online, too, at raritanengineering.com

[Terra Nova]

Originally Posted by a64pilot

OK, first the inlet of the holding tank should be at the top of the tank, so that unless it's completely full, you can't get any back flow from the tank...

This. Accept no substitutes.

[Cheechako]

Does your holding tank fill on the top? It should.

[steve77]

I was having a problem flushing our heads because the vented loop on the intake side prevented adequate vacuum to form to draw water to the pump. If you have trouble flushing, you may want to consider removing that vented loop.

[nautical62]

The purpose of a vented loop is to prevent raw water and sewage from siphoning back if your system would otherwise allow such a siphon - Very important in a direct discharge system (which you don't have) In your case, you could also develop a siphon if your unvented discharge line enters the holding tank below the sewage level and that sewage level is higher than your head. If your discharge line dumps into the top of the tank and the tank is vented, then the air between the sewage and the hose will prevent siphoning.

It sounds like you simply have sewage slopping back because your loop is too low when heeled. That's a matter of the loop height, not whether or not it's vented.

Joker valves are one-way valves. Replacing it with a new one might help, but it only takes a little particle of something stuck or a little loss of integrity for them to start slowly leaking backwards if there is back pressure. This is why many heads slowly fill a bit after sitting as the water in the discharge hose slowly leaks back in. Personally, I wouldn't rely on the head's joker valve to prevent sewage in the pipe from back flowing. Better to stop sewage from flowing back into that section of hose by raising the loop. (Though replacing the joker should be fairly simple and inexpensive)

Adding a one-way valve between your loop and the tank may be another solution, but that may add a bit more resistance when pumping. Not too sure on that - but thought I'd throw it out as an option to look into.

If your discharge hose enters your holding tank near the bottom, re-plumbing it to the top may solve your problem.

[Mycroft]

Turns out that the reason there's an anti-siphon loop is because after the loop is the Y-valve between the tank and overboard.

[Cheechako]

Originally Posted by steve77

I was having a problem flushing our heads because the vented loop on the intake side prevented adequate vacuum to form to draw water to the pump. If you have trouble flushing, you may want to consider removing that vented loop.

Yes, I've had the same issue. Gurgly intake after installing the loop there. Sometimes I think a mounted Ball valve would be better. they sell ones with the bulkhead mount cast as part of the body.