Holding tank diverter valve

I'm installing a replacement holding tank. The output of the tank is on the bottom. Standard 1 1/2 " barbs, etc. I want to put a diverter valve right after the output of the tank so I can direct the sewage to a macerator, then to a thru-hull for direct discharge (where allowed)...or...direct the flow to a deck pump out when in a marina. The question is regarding the height of the diverter valve in relation to the holding tank outlet. Would it work if the diverter valve was located at the same height as the top of the holding tank? Or do I rely on gravity and have to locate the diverter valve at the lowest possible location? Ideally, I would like to mount the diverter valve on a bulkhead as opposed to the bilge (there is no way to locate the valve lower than the holding tank outlet). Any thoughts, advise, or experience is appriciated.

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If I understand your set up, it sounds like mine. If so you don't need a diverter valve, just a tee with hose barbs. One hose from the tee goes to the deck pipe and one hose goes to the pump. A shutoff valve at the tank outlet might make things easier when you need to work on the pump.

Your idea of mounting the valve on a bulkhead is fine.

One boat we owned had the macerator pump and Y valve mounted on top of the holding tank. The valve connected the fitting at the bottom of the tank to either the macerator pump or to the deck fitting for pump-out. The macerator pulled off the bottom of the tank and pumped overboard.

The Jabsco 18590, which we had, is a common macerator and specs say will prime up to 4 feet dry so you don't have to depend on gravity. The pump will pump the tank out or a dock-side pumpout will use vacuum to empty the tank.

If the pump is higher than the tank top it is not quite as messy to disconnect the pump when you have to service it. Otherwise I would recommend installing a PVC ball valve on the tank outlet so you can shut the tank off when you need to open the lines. If you discharge below the waterline an anti-siphon loop is also recommended.

Thanks for the responses! To HopCar, I already have the diverter valve, and the local C.G. folks like the setup. A cut off valve at the holding tank outlet is a great idea I didn't consider; thanks. Just to clarify, to av8r, my macerator is mounted downstream of the diverter valve, so I will be relying on suction from the pump to pull the waste from the tank. As I understand from your response, I guess I should be o.k. with that? I like the idea of having the valve bulkhead mounted at just below the top of the tank in case things need to be taken apart. Any other things I should consider? I'll be testing the system with fresh water, of course, but any other things I should consider?

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I have a similar set-up, and can tell you the so-called self-priming to 1 metre claim of my TMC macerator as always been dead wrong. I had to wangle a series of valves to divert some water back down to that pump to prime it before it would pump. Having said that, I think the Jabsco version is better, and will manage it ok, and as my TMC is quite rusted now, I will replace it with a Jabsco. Having a diverter valve with optional padlock or peg lock makes it much better if inspected than a simple T, I suspect, and your pollution laws are tougher than ours.

RMoore, My two cents worth based on your description! If you elect to go without a valve, you had best ensure that the macerator side of the equation does not leak air, for if it does, the vacuum pump out will not work efficiently. There also exists the possibility that it may suck sea water into the system, rather than pump out your holding tank. Path of least resistance, etc. My gut, I would install the valve for redundancy.

Finished testing the system today and am happy to say that everything worked fine. The diverter valve is mounted on the bulkhead with the outputs about 3/4 the height of the top of the holding tank. The macerator sucks the tank nearly dry, and I'm happy to say there are no leaks! Thanks for all the advise and happy boating to all!

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Congrats, you might have even motivated me to get onto the job I have been putting off, of installing a more robust diverter valve, which is also more accessible, as the ones I have been using, although made of Marelon, are breaking off when not used for a period and getting stuck. The damn handle breaks off. I am referring to the one which sends to tank or through hull. The stout Jabsco variety I use near the tank for diversion to macerator or to deck pump-out is much better - more expensive though of course, but if needs must...

I am in the Great Lakes so no overboard discharge is possible. I have wondered if and when I get to a point where overboard discharge was an option if it could be achieved with a pump connected to the deck fitting.

SaltyDog said:

I am in the Great Lakes so no overboard discharge is possible. I have wondered if and when I get to a point where overboard discharge was an option if it could be achieved with a pump connected to the deck fitting.

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That's really what a Y valve does for you. On my boat the Y valve is installed about 2 feet below the pump out fitting so that one outlet goes to the deck fitting and the other to the macerator.

Ron

I have wondered if and when I get to a point where overboard discharge was an option if it could be achieved with a pump connected to the deck fitting.

Works perfectly , and with no hassles from the po-po police.

" I have wondered if and when I get to a point where overboard discharge was an option if it could be achieved with a pump connected to the deck fitting."

Sure you could but you'd then have to carry around a stinky bunch of hoses and a pump. If you ever find yourself wanting to discharge overboard, it will be worth the effort to install a thru-hull.

I think I would come out smelling better with a temporary solution than having to disable a new installation when returning to inland waters. As long as the hoses are long enough to be deployed over the side into the sea, I'd think that flushing the pump and hose would be simple enough. Using same components as the emergency manual bilge pump is what I had in mind. KISS

First let me say, Ewww!
Since you're determined to do it, you can get the fittings you need to connect the hose to your deck fitting from Edson.
Waste Deck Fittings & Adapters : Edson Pump Store

For those that are fed up with yachty stuff with limited use and short life the Hayward true union 3 way valves are a good option.

WE have used the 2 inch series 80 with series 80 plastic pipe for both waste and bilge compartment selection.

Hayward® LA Series Three-Way Lateral Ball Valves

First off I am not determined to do it. Just want to be prepared should the need (holding tank) arise on the loop.

Some things can be held off.

Modifying the sanitation system is one. The naturally occurring is one (and/or two) that can not. There is the 5 gallon pail method, but(t) that doesn't appeal to some.

Just want to be prepared should the need (holding tank) arise on the loop.

ON the loop you will be on a great many rivers and in lakes that ARE folks DRINKING WATER!!!

Yes a holding tank will be REQUIRED !!!!!!

I know pumpout is available in the freshwater areas. 55 gallons goes a long way. I would not even consider doing that. Our marina includes fuel dock pump-outs in the slip fee. They provide in-slip service at a charge. Places that charge cost about the same as we generally tip if our guys that assist during normal attended service hours. We have 24 hour availability so even the sailboats are not intimidated by tips. lol.

Of all the boaters on Lake Michigan I know, none of them discharge. The river rats not so much. No excuse, it's just wrong.

With the number of folks on here that do discharge I figured there must be some need for it.

With the number of folks on here that do discharge I figured there must be some need for it.

The need arises from extended stays at the hook .Or the few offshore boats that are far enough out and dont want to haul the weight.

FF said:

For those that are fed up with yachty stuff with limited use and short life the Hayward true union 3 way valves are a good option.

WE have used the 2 inch series 80 with series 80 plastic pipe for both waste and bilge compartment selection.

Hayward® LA Series Three-Way Lateral Ball Valves

Click to expand...

Wow. The prices of these valves is high!!a 2"valve is $300

The prices of these valves is high!!a 2"valve is $300

And a good Obendorfer or Galley Maid waste pump is a grand ++.

Just depends on weather you enjoy fixing waste stuff , or boating.

KISS

FF said:

The prices of these valves is high!!a 2"valve is $300

And a good Obendorfer or Galley Maid waste pump is a grand ++.

Just depends on weather you enjoy fixing waste stuff , or boating.

KISS

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In defense of that $300 valve, it does come with threaded unions...not just barb fittings, which really helps if you wish to go with hard pipe versus hose for a lot of your sanitation plumbing.

FF said:

The prices of these valves is high!!a 2"valve is $300

And a good Obendorfer or Galley Maid waste pump is a grand ++.

Just depends on weather you enjoy fixing waste stuff , or boating.

KISS

Click to expand...

Waste pump ? This is just a valve. A 3 way valve at WM is $100-150 I guess I am just confused

My fairly new Sealand tank has two openings for waste out. One for the dockside pump out and another for the macerator. No valves needed.
I used sch40 pvc for all piping except the vent.

motion30 said:

Waste pump ? This is just a valve. A 3 way valve at WM is $100-150 I guess I am just confused

Click to expand...

Those are 1 1/2" valves without unions. Fred's valve is 2" schedule 80 with integral unions. Apples and oranges.

The Hayward can be removed in seconds should it ever be needed.

In addition the handle can be removed and a reach rod used to operate the valve from outside the area its located in.

WE have these valves to direct bilge water to the bilge pump , as the boat has WT bulkheads .