How to convert a Jabsco electric head to fresh water flush

[CatNewBee]

We have Jabsco seawater flush toilets installed, and I want to convert one of them to fresh water flushing to reduce odors in the owners hull and also calcification of the sewer hoses.

I am thinking about adding a T connection and a one way valve into the pressurized fresh water system and go with a short hose to a 2 way vent to the salt water intake from the flushing pump. Then I can close the sea cock and the pump will in theory get the fresh water from the pressurized fresh cold water system.

One uncertainty is, will the water pressure on the line cause a bypass of the pump and simply drain the tank into the head, or will the pump and eventually an existing electric vent prevent the fresh water from flowing into the bowl if the switch is not pressed.

Has someone done this conversion and what is needed? Do I have to add an additional electric vent to control the fresh water flow? I really do not want to run a separate pipe from the water tanks to the toilet just to circumvent the pressure pump.

Thanks for your hints.

It is a Jabsco QuietFlush with external salt water pump.

[CatNewBee]

I have checked the installation, it seems the salt water goes straight from the troughhull via a hose to the strainer on the pump and from the pump to the bowl, no solenoid valve visible so far...

[peghall]

Toilets designed to use pressurized fresh water don't have an intake pump...instead there's a solenoid valve--either built into the toilet along with the necessary vacuum breaker and backflow preventer valve, or installed in the intake line from the cold water line to the head sink. The solenoid valve--which must b wired to the flush button--acts like a faucet...opening to allow pressurized flush water to flow, closing to block it.
Circumventing the fresh water pump is the last thing you should do because that wouldn't provide the protection from bacteria in the bowl migrating into the fresh water plumbing that pressurized flush water and solenoid do. And you'd still need the siphon breaker and backflow prevention valve.
Jabsco does offer a fresh water conversion kit for your toilet (37245) and it's the safest way to do it, but that kit is expensive...best price I could find was $499 at Defender. You might be able to offset the cost a bit by selling the remote intake pump and sea water pump and motor assembly...or you could re-purpose the intake pump to be a washdown pump.

I'm sure at least a couple of people will reply with instructions for a DIY conversion. It's something that every toilet mfr strongly recommends against, but it's your boat, your money and your decision.

Just saw your post re solenoid valve...
Any solenoid valve in a sea water toilet would be on the vented loop that should be in the intake line between the pump and bowl on any toilet installed below waterline.



--Peggie

[CatNewBee]

Thank you for your post. The heads are factory installed from Lagoon, no vented loop for the flush on both sides. The hoses go straight tobthe pumps and then to the bilges, but maybe they are placed above the water line, so should be ok.

I found the Jabsco solenoid online, quite expensive, but contains the backflow protection valve. I want to make it dual way, so I can switch between fresh and sea water. Sea water flush makes sense on passages, while at anchor there is plenty of energy to make enough water for all purposes.

I have to figure it out and make a DIY solution. There are cheep plastic and brass N/C solenoid valves, and also reverse flow protection valves, could be an easy electric switch solution.

I am thinking about a T junction to the bowl, on both sides reverse flow protection valves, one side goes to the sea water pump, the other side to the solenoid and the pressurized fresh water line, switching would be done simply on the push button output between the pump and the solenoid.

[peghall]

Before you buy or do anything, I strongly recommend that you have a chat with Jabso's marine toilet guru about all this...his name is Paul Campagna... his direct line is 978.282.5246


--Peggie

[Russ]

Very dangerous from point of view of backflow and contaminating FW supply. You must use a FW head or the jabsco conversion. Anything less and y’all be sick puppies no matter how many check valves etc you install.

[newtonsailor]

Originally Posted by CatNewBee

We have Jabsco seawater flush toilets installed, and I want to convert one of them to fresh water flushing to reduce odors in the owners hull and also calcification of the sewer hoses.

I am thinking about adding a T connection and a one way valve into the pressurized fresh water system and go with a short hose to a 2 way vent to the salt water intake from the flushing pump. Then I can close the sea cock and the pump will in theory get the fresh water from the pressurized fresh cold water system.

One uncertainty is, will the water pressure on the line cause a bypass of the pump and simply drain the tank into the head, or will the pump and eventually an existing electric vent prevent the fresh water from flowing into the bowl if the switch is not pressed.

Has someone done this conversion and what is needed? Do I have to add an additional electric vent to control the fresh water flow? I really do not want to run a separate pipe from the water tanks to the toilet just to circumvent the pressure pump.

Thanks for your hints.

It is a Jabsco QuietFlush with external salt water pump.

I did this conversion on my boat. Fairly easy. Jabsco makes the needed part. Jabsco 37038-1012, Marine Toilet Repair, Head Solenoid / Anti-Syphon Valve, 12 Volt
You remove your sea water intake hose from the 12V intake water pump activated by your toilet bowl fill switch. put that hose to the output of the jabsco anti-syphon valve, wire your switch to this valve instead of the head fill pump, run a hose from the input side of the valve to your fresh water supply and make sure you put the valve a few feet above the toilet as stated in the instructions so the anti- Syphon works. for extra credit, use a new hose from the valve to the toilet. There is no way for head waste water to make its way into your fresh water supply as the fresh water only enters at the top of the bowl and from a higher level, with an anti-syphon valve, and this is how all the factory fresh water heads are plumbed.
In any event I have used it for a few years now on a Cat we took out of charter. Works great, got rid of the calcium and smell, and no one has gotten sick so far :-)

[CatNewBee]

Thanks, I will check it out. I was thinking about a switchable solution, so I can use both, fresh water (near shore, at anchor, in marinas) and salt water (on ocean passages to conserve fresh water if something breaks) for flushing.

But maybe I simply convert one head to fresh water and leave the guest head to salt water...