Has anyone here converted a VacuFlush toilet to use sea water?

[peghall]

Over the years I've come across a few people who've done it successfully, so I know it can be done by disconnecting the flush water inlet line from the fresh water line and installing a remote intake pump and a new line to the toilet bowl...but I can't remember the details. If anyone here has done it or knows someone who has, I'd appreciate hearing from you.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[senormechanico]

Peg,
I did exactly that on a new Thetford Nano Eco.
I didn't have enough room for another raw water pump, so I added a couple of diodes to the supply line from my salt water anchor washdown circuit to energize the pump during flush. I also added a tee for the flush water.

My washdown pump is a 6 gpm/60 psi unit and the one supplied by Thetford is only 3 gpm, so I inquired about the ability of the head to be able to evacuate water above the input rate !

They assured me it would work fine if I was able to do the electrical end of my plan.
It works without any problems.

[peghall]

You already had a flush button that could be rewired to run the pump. The VacuFlush doesn't...stepping on the pedal or pushing its flush button opens an "air valve" to which a pressurized water line is attached...kinda like opening a faucet on a sink. So the problem here is how install a wired flush button in the head to run the pump without the need for the owner pay a marine electrician more than it's worth. There's not much I don't know about sanitation plumbing, but electrical is a whole different field of expertise I've successfully managed to avoid so far.

[senormechanico]

Peg,

You're right of course.

A vacuum switch sensing atmospheric pressure below the bowl valve would be needed, and probably a relay to send power to the pump.

Not impossible, but some DIY timing and flow adjustments might be needed.

[Scott Berg]

Hi Peg; most people who have done this add a pressure pump with a pressure switch that is activated by the pedal opening the valve (and let the pump use salt water in place of the fresh water inlet)
. My question is why?

[peghall]

My question is why?

27' "pocket trawler" only carries 20 gal fresh water...how any builder could possibly think that's anywhere near enough even without a toilet that uses fresh water is amazing! No space to upsize the wr tank or add another one without giving up too much storage..and they like to gunk hole for a week at a time.

Toilet isn't actually a V/Flush...it's the self-contained SeaLand 711-M28 "Marine Traveler" that uses the same RV bowl as the V/Flush. I've always like this system 'cuz it holds as many flushes as a 40 gal tank connected to marine toilet. Owner came to me to find out if it can be converted to sea water. I know it's been done, know what's needed to do it... just need to know how to do it.



Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein