new head installation

[sakajote]

Request for help:

I was installing a new head this past weekend. I chose a GROCO thinking it would mate with the installation holes of the old GROCO--This turned out not to be true if you are considering a similar task.

The question is on vented loops. A number of books recommend inclusing these in the waste line. I dutifully purchased same but was confounded trying to install one, above the projected heeled water line that did not interfere with seating or with the opening the door to the wet locker. Does anyone have advice? or alternatively, can anyone opine as to the necessity? The old head plumbing did not include one and I dont know that it was a problem, though it was not a focus, the leaking/cracked pump was the issue at hand.

Thanks,

[rtbates]

If your waste line only runs to your holding tank (the way it should be) NO you don't need one. If on the other hand your waste line runs directly to a below the waterline water seacock that you tend to leave open then YES. The purpose of the above water line loop is to prevent a siphon action. Can't siphon if the seacocks is closed.

randy 25D Seraph #161

[sakajote]

Randy--Thanks for the reply! I have a diverter valve that allows selection between seacock and holding tank--it is always in position to route waste flow to the holding tank. From what I gather from your post I would not need the vented loop. I am curious, it would seem like there would need to be a check valve somewhere in the line to prevent backflow--maybe there is--I am new at this part.

Thanks again, D

[rschattman]

I respectfully disagree. You need the anti syphon if you have a direct line to seacock regardless of your use of the overboard option. If you have completely disconnected this option and are only feeding directly to your holding tank, by all means remove the extra line... it can only create odor problems and take up space. Richard Schattman - S/V Solstice (CD 36).

[rtbates]

The best thing you could do is eliminate the line that runs from your head to direct overboard seacock. Pump 100% of your waste into your holding tank. At the tanks outlet, there needs to be two paths thru a Y valve. One goes to your pump out fitting the other goes overboard. With this system there is never a question of accidently diverting waste overboard as your guests snorkel around the boat while the Coast Guard checks your documents. Eventually this will be the only 100% approved in all locals system. In the mean time I believe in some areas you must have the Y-valve that allows direct discharge wired so that all waste goes to your tank. West Marine has a very good discription of waste systems in their catalog. No check valve other than whats at the head. ALWAYS KEEP YOUR HEAD IN THE DRY FLUSH POSITION and if possible(can you reach it?) ALWAYS keep the intake seacock closed when not in use.

randy 25D Seraph #161

[sakajote]

Randy and Richard--thankyou both. It would seem that even with a waste line to the seacock from the head, since it goes thru the diverter valve which is always turned to the holding tank, siphoning/flooding would not be a problem as long as there was no hose break. That said--I like the idea of eliminating the diverter valve and running a straight line to the holding tank. Since there is no apparent reason to replace the line from the diverter valve to the tank--I suppose I can replace the diverter valve with a coupling. I have replace the hose from the valve back to the head.
As you say, this will ensure no overboard discharge and would be non-contentious with CG inspection.

Splitting the holding tank outflow line into a pump-out and discharge combo can be a winter project if needed.

Again thanks, Dixon

[Guest]

Question....Isn't it necessary to install a vented loop on the intake side as well? Esp if one leaves the seacock open while underway...

Sean

[John Ring]

In response to Sean's (excellent) question, you can't put a vented loop on the intake side of a head. It would allow air into the line, rather than allow the line to pick up water needed to flush.

John

[Troy Scott]

Folks,

I know this is old, but I just came across it. You DO need an anti-siphon loop in the toilet intake line, but it has to be inserted into the line between the pump and the bowl. If the loop is installed between the seacock and the pump, as John Ring wrote, it won't work.

[2tocruise]

I replaced the head this spring. Same Groco HF model that was in the boat for the last 20 years, and no, the mounting bolts did not line up for me either.

To offer another opinion to the vented loop question: I installed a vented loop on the suction (intake) side of the pump between the seacock and the head pump. I didn't want to change the nice 12" or so piece running from the pump to the bowl with another big mess of hose. On it's own the vented loop does allow air into the pump; but that is quickly fixed by unscrewing the vent cap on the loop and inserting a small piece of open-cell foam. (I used a tiny piece from one of the berth cushions). It stops up the vent just enough to allow the pump to easily pull water, but not enough to negate having vented loop.

We used the head this way all season and never had any problems. Of course, we also only open the head seacock when the head is being used. No sense inviting water inside the boat for no reason.

[mexsailor]

My out hose from the Jabsco goes directly to the 6 gal. holding tank. From the holding tank I have three hoses.
One goes to the macerator and then to the discharge thru-hull. Another one goes to the deck fitting for pump outs. The third one, much smaller, is a vent hose that runs to the side of the cabin top.
Normally, both thru-hulls are in a closed position.
If, for any reason, either thru-hull is not closed and we're heeling, could I siphon water up into the holding tank or Jabsco? I didn't install a vent hose even though I thought about and even bought the items I needed. It was such a tight install and took up more room than I wanted to live with. (Not much room on a CD25 for a head installation. )
Is this hazardous or what? Should I install it? If yes, then I presume between the intake thru-hull and the Jabsco, correct?

[Troy Scott]

Mexsailor,

On the intake side of the toilet, if the seacock is left open and the pump on the toilet happens not to be sealing well, and if the toilet is below the waterline, water will eventually make it's way into the bowl, fill it up, overflow it, and possibly sink your boat. This has happened many times to many boats. When the toilet is new, it may seem OK to leave the seacock open. After all, once we've observed that the seacock is open and the toilet isn't filling on it's own, we tend to decide that it's OK. But the pump will eventually leak and then it won't be OK.

A siphon break (vented loop) on the intake eliminates any tendency for the bowl to fill and overflow on it's own. Now as for the location of the siphon break: Ideally it will be between the pump and the bowl. You can also install it between the seacock and the pump, but with the siphon break in this location you have to work harder to move water, because the pump will be pulling air through the siphon break along with trying to pull water up over the loop.

If you have a seacock for moving liquid from a holding tank into the ocean, and if the holding tank is below the waterline, there is an excellent chance that the ocean will flow INTO the seacock when you open it unless you have a siphon break between the seacock and the liquid. Here, the vent goes between the pump and the seacock.

We never want to pull liquid through a vented loop. You want pressurized or "pushed" liquid moving through there.

Without a vent hose I'm surprised that your holding tank readily accepts fluid from the tiolet. I suppose that when you pump out the holding tank, air is entering the tank through the "joker" valve on the toilet. You lack of a vent hose for your holding tank would definitely slow the flow of ocean water into your holding tank when the seacock is open, but it probably won't stop it. Your macerator pump may also have some provision for backflow prevention. However, this type of device, like the pump on the toilet, is only a secondary line of defense against flooding. You need a vented loop between the macerator and the seacock.

Now, about the necessity for vented loops between the macerator pump and the seacock and between the intake seacock and the bowl: I realize that anyone who is quick witted should be able to open a seacock while turning the macerator on at the same time, then reverse the maneuver when finished. Theoretically there shouldn't be a problem. Likewise, we should always keep closed the seacocks we don't need open. However, when valves, pumps, etc. get a little age on them, they don't always work ideally. Imagine that one of your seacocks leaks very slowly when closed, like a drippy faucet. If just one vented loop is left out from one of those locations where it "can't hurt and might help", that drippy seacock might eventually sink your boat.

[Carter Brey]

Mexsailor,

On the intake side of the toilet, if the seacock is left open and the pump on the toilet happens not to be sealing well, and if the toilet is below the waterline, water will eventually make it's way into the bowl, fill it up, overflow it, and possibly sink your boat. This has happened many times to many boats. When the toilet is new, it may seem OK to leave the seacock open. After all, once we've observed that the seacock is open and the toilet isn't filling on it's own, we tend to decide that it's OK. But the pump will eventually leak and then it won't be OK.

A siphon break (vented loop) on the intake eliminates any tendency for the bowl to fill and overflow on it's own. Now as for the location of the siphon break: Ideally it will be between the pump and the bowl. You can also install it between the seacock and the pump, but with the siphon break in this location you have to work harder to move water, because the pump will be pulling air through the siphon break along with trying to pull water up over the loop.

If you have a seacock for moving liquid from a holding tank into the ocean, and if the holding tank is below the waterline, there is an excellent chance that the ocean will flow INTO the seacock when you open it unless you have a siphon break between the seacock and the liquid. Here, the vent goes between the pump and the seacock.

We never want to pull liquid through a vented loop. You want pressurized or "pushed" liquid moving through there.

Without a vent hose I'm surprised that your holding tank readily accepts fluid from the tiolet. I suppose that when you pump out the holding tank, air is entering the tank through the "joker" valve on the toilet. You lack of a vent hose for your holding tank would definitely slow the flow of ocean water into your holding tank when the seacock is open, but it probably won't stop it. Your macerator pump may also have some provision for backflow prevention. However, this type of device, like the pump on the toilet, is only a secondary line of defense against flooding. You need a vented loop between the macerator and the seacock.

Now, about the necessity for vented loops between the macerator pump and the seacock and between the intake seacock and the bowl: I realize that anyone who is quick witted should be able to open a seacock while turning the macerator on at the same time, then reverse the maneuver when finished. Theoretically there shouldn't be a problem. Likewise, we should always keep closed the seacocks we don't need open. However, when valves, pumps, etc. get a little age on them, they don't always work ideally. Imagine that one of your seacocks leaks very slowly when closed, like a drippy faucet. If just one vented loop is left out from one of those locations where it "can't hurt and might help", that drippy seacock might eventually sink your boat.

As someone who is about to redesign completely his head installation, I have to ask this question: doesn't poop spurt up through the vent hole in the loop between the macerator and the overboard discharge seacock when pumping overboard? I've been unable to find this unpleasant question addressed anywhere. Does one have to T a vent hose from the loop to the tank vent through-hull? I understand siphoning and the reasoning behind the two vented loops, but as someone who regularly maintains his Spartan seacocks and is absolutely fanatic about keeping them shut when not actually in use, I am mightily resisting the notion of vented loops, or at least the one on the stinky side.

Thanks for clearing this up,
Carter

P.S. There's an article in the March/April issue of Good Old Boat by a man who redesigned his head installation without vented loops, depending on his practice, like mine, of keeping seacocks closed and lecturing his guests on the need. He's had no problems with the installation. I know: what if one of your incontinent guests has Attention Deficit Disorder? I would always double-check the seacocks after a guest's use of the head.

[Warren Kaplan]

but as someone who regularly maintains his Spartan seacocks and is absolutely fanatic about keeping them shut

Carter,
Whew! So anal!!! I can see why you're totally redesigning Delphine's head compartment!!

[Carter Brey]

but as someone who regularly maintains his Spartan seacocks and is absolutely fanatic about keeping them shut

Carter,
Whew! So anal!!! I can see why you're totally redesigning Delphine's head compartment!!

Actually, Warren, I have to replace the hoses, which are old, ribbed and permeated, and therefor stink. I figured as long as I was shelling out for some 25 feet of the fancy Trident 101 Super Duper Sanitation Hose, I might as well do some upgrading of the whole shebang so I can evacuate the holding tank overboard while off Oyster Bay.

Note to the USCG: JUST KIDDING.