Converting Heads to option for Freshwater Flush

[Mac G]

We currently have two raw-water flush heads.

Am replacing all the hoses with new as a matter of routine maintenance and would also like to add ability to flush with pressurized Freshwater too, but still be able to go back to seawater flush if low on water or in the Great Lakes.

My idea is to plumb-up a system of valves and switches to allow going back and forth between raw-water flush versus freshwater flush depending on where we are crusing. So, for example, will flush with freshwater when in ocean and "raw-water" when in the Great Lakes.

Other than adding some new valves and switches, will this simply require the addition of a 12V solenoid/siphon break between my freshwater source and the head? Or is there more to it than that? What am I missing?
Anyone else have such a set-up?

My idea is to mount a control board down in the engine room where the selection can be made by flipping certain switches and opening/closing certain valves.

Is the addition of the solenoid to control the 40 psi freshwater input all that I need to make this work?

Please advise

Thank you

 

[Ken E.]

A TF contributor, Peggy, is very knowledgeable about all- things marine heads and has helped me in the past. Maybe she will chime in.

I had Raritan Crown heads which are raw water. They worked fine but smelled bad, owing to what's in seawater, especially if it sits around unused for a few days. I removed the Crowns and replaced them with Raritan SeaEra's, which are freshwater flush. No more smells and very powerful, although they aren't quiet. My suggestion would be to go simple and just flush with fresh water, forgetting raw water.

There is another problem with what you are trying to do, at least with Raritans. My Crown heads had an internal pump to lift and deliver sea water to the toilet. The SeaEra's use pressurized water from the boat's potable water system, in conjunction with a vacuum breaker to prevent back flow. The toilets are fundamentally different. With a manifold and valves, you could probably achieve what you're trying to do but I wonder if it would be worth the effort.

 

[HeadMistress]

Raritan makes TWO versions of the SeaEra: the basic SeaEra is a sea water toilet that should NOT be connected to the fresh water plumbing...the SeaEra QC is the fresh water version.


All sea water toilets DO have an intake pump...Toilets designed to use fresh water do not...they must use only pressurized fresh water and require a solenoid valve--with vented loop--that acts kinda like a faucet, opening to allow the water to flow into toilet, closing to block it. They do have the built-in siphon breaks and backflow preventers that protect the fresh water supply from contamination that sea water toilets don't have... making it a bad idea to connect any sea water toilet to the boat's fresh water plumbing--something that every toilet mfr warns against.


So if you want a toilet that uses fresh water, buy a toilet designed to use fresh water.



--Peggie

 

[Mac G]

Okay. Have talked to Peggy (Thank you) and read many on-line posts on why one cannot or should not convert a raw water flush head to freshwater flush.

Have seen many posts on other forums suggesting that simply buying the freshwater model would be easier. Yes. I get that.

And from the manufacturer's perspective - they want you to buy their other model, not convert your existing one!
Or from their legal department's perspective, they don't want you to try, end up screwing it up, and suing them when someone gets sick or you sink your boat!
As a retired lawyer I get that too.

I understand all that, however, there is nothing wrong with our current toilets.
And as a retired geezer who likes the challenge of tool projects I am always keen on out-of-box ideas and have fun buying parts and designing these sorts of things.

We want to be able to cruise the Atlantic and Great Lakes and be able to switch back and forth depending on where we are crusing.
So, along those lines, please see the attached sketch and tell me why this would not work.

Am looking for reasons related to specifically to physics, engineering and science on where my design is flawed.

I do not see how it would be physically possible to contaminate my freshwater system with either seawater or toilet water with this set-up.
Yes the solenoid could fail and drain my water tanks while it floods the head; we turn off the pump (and close all our seacocks) when we leave the boat anyway.

Am always open to learn and admit fault as it was instilled in me long ago that the day you think you know everything is the day you stop learning; so
please tell me what I am missing and I will eat crow.

But please do not suggest that this seems like a lot of extra work because that is what gets out of bed in the morning!

Please advise

Thank you

PS - have left all electrical connections to solenoid and raw water pump off this diagram for ease of reading as only looking for plumbing input here.

 

[Comodave]

I really like Raritan Marine Elegance heads. They are awesome. They are available with an option that has both freshwater and sea water flush.

 

[mvweebles]

Okay. Have talked to Peggy (Thank you) and read many on-line posts on why one cannot or should not convert a raw water flush head to freshwater flush.

Have seen many posts on other forums suggesting that simply buying the freshwater model would be easier. Yes. I get that.

And from the manufacturer's perspective - they want you to buy their other model, not convert your existing one!
Or from their legal department's perspective, they don't want you to try, end up screwing it up, and suing them when someone gets sick or you sink your boat!
As a retired lawyer I get that too.

I understand all that, however, there is nothing wrong with our current toilets.
And as a retired geezer who likes the challenge of tool projects I am always keen on out-of-box ideas and have fun buying parts and designing these sorts of things.

We want to be able to cruise the Atlantic and Great Lakes and be able to switch back and forth depending on where we are crusing.
So, along those lines, please see the attached sketch and tell me why this would not work.

Am looking for reasons related to specifically to physics, engineering and science on where my design is flawed.

I do not see how it would be physically possible to contaminate my freshwater system with either seawater or toilet water with this set-up.
Yes the solenoid could fail and drain my water tanks while it floods the head; we turn off the pump (and close all our seacocks) when we leave the boat anyway.

Am always open to learn and admit fault as it was instilled in me long ago that the day you think you know everything is the day you stop learning; so
please tell me what I am missing and I will eat crow.

But please do not suggest that this seems like a lot of extra work because that is what gets out of bed in the morning!

Please advise

Thank you

PS - have left all electrical connections to solenoid and raw water pump off this diagram for ease of reading as only looking for plumbing input here.

It would probably work just fine. Risk of cross contamination between raw water and fresh water is minimal (but not zero). I don't know your exact head, but many/most raw water heads recirculate some effluent with the inlet water, especially as they age.

The recommendation from the expert Peggie Hall (who has no profit motive whatsoever) is to NOT do this.

I have to ask what problem is being solved. Yes, risk is small, but benefit also seems de minimus. There's a bit of work and connections to be made up - is the juice worth the squeeze?

Peter

 

[Mac G]

Curennt setup is raw water flush now.
All that infrastructure is in place.
Current toilets only have motors at their base to grind up and send out whatever is in the bowls. Out the bottom only. No water recirculation. New water gets added from top.
The raw water enters from a fitting on the top rear of the toilets and is fed by separate raw water pumps located on the other side of bulkheads in completely separate spaces.
So all I would need to do is add those T fittings and some valves and other fittings for the freshwater; but the raw water side is already in place and functional.
My plan is to mount all that stuff on a solid wood backboards (raw water pump, solenoid, back flow preventer, electrical selector switch, etc.) on the same bulkheads where the existing raw water pumps are currently situated.
Then all I would need to do is go to those control boards and flip some valves and switches, etc. to make the conversion.
We primarly cruise in New England so we would flush with freshwater until our tanks got low; but when going into the Great Lakes we could switch back over to "raw water."
Since the toilets are clean and functional and the raw water set-up currently works the thoguht is the cost of a couple of valves and fittings is cheaper than two new heads.
Plus, as mentioned, I enjoy the challenge of these sorts of projects.
Regarding salt water contamination, if the seacocks and ball valves after the raw water pumps are both closed how could sea water possiblly get into the pressurized freshwater system?
Thank you for analyzing and critiquing.
This is how I learn.

 

[Marco Flamingo]

Peggie,

We have a Vacuflush system that has worked great. But I remember the sales listing claiming that the head had been converted from raw water to potable water. My question is whether I need to check if the Vacuflush was "converted" to potable or the Vacuflush was a replacement for the old raw water head (and therefore has the built-in backflow protections). I assume both are possibilities. Where do I look and what do I look for?

I had also toyed with the idea of a dual-water system. We carry only 150 gallons of fresh, which goes away much faster than our 250 gallons of fuel, requiring marina visits where marinas are few and far between. In those areas, pumping directly overboard is allowed (saving filling up our 15 gallon black water tank), but we are still using up our fresh water. Utilizing saltwater would extend our marina-free cruising, but if I understand correctly, it's a complication not worth attempting (unless Mac G solves the conundrum).

 

[HeadMistress]

There is a safe way to do it: use the head to sink to supply the fresh water. You'll need to tee or wye one end of a new line into your toilet intake line, the other end into your head sink drain line. Unless your head sink drain is below the waterline--common on sailboats, rare on power boats--you'll also have to install a seacock or other means of closing the sink drain line to hold water in the sink when you want to flush with fresh water.. Flush normally with sea water until you want to use fresh. To do that, close the drain and fill the sink with water...flush the toilet. Because the drain is closed the toilet will pull the water out of the sink. This not only allows you to flush with fresh water, it also provides a means of rinsing all the sea water out of the entire system--head intake line, pump, channel in the rim of the bowl and the toilet discharge line, eliminating the odor problem created by sea water left to sit and stagnate while the boat sits without any risk of cross contamination...Or you can flush using clean water (NEVER gray water, soap scum, body oils etc will "gum up" the toilet pump) from the sink all the time.


Be careful not to let impellers in sea water toilets run dry...that "fries" impellers.



--Peggie

 

[HeadMistress]

We have a Vacuflush system that has worked great. But I remember the sales listing claiming that the head had been converted from raw water to potable water. My question is whether I need to check if the Vacuflush was "converted" to potable or the Vacuflush was a replacement for the old raw water head (and therefore has the built-in backflow protections). I assume both are possibilities. Where do I look and what do I look for?

VaucFlush toilets are designed to use pressurized fresh water.They can be converted to use raw water and owners whose fresh water is in short supply have done it, but that requires adding a remote intake pump and disconnecting the fresh water intake line...it does not allow switching at will.
So I'm 90% certain the VF was a replacement for a sea water toilet.


--Peggie

 

[Mambo42]

Originally our toilets had a sea water flush, but after a technician told me that salt deposits could block the functioning I simply disconnected the water inlet of the toilet (to salt water) and connected a sweet water hose (simply split the shower hose). The waste hose has no connections to the water supply, so I would be very surprised if our water tank gets contaminated by toilet water.
If my assumption is wrong please let me know, then I will have to change the set up.

 

[Comodave]

I am not sure but at a minimum I think it should have a back flow preventer.

 

[Bmarler]

like dave says, install a backflow preventer in between the source valve and vented loop. those two things will keep you safe.
or, looking at the vacuflush water supply, there's a valve at the pedal, and the vent is behind the bowl. nothing complicated. if you wanted to mimic that, a solenoid valve in place of the backflow preventer would let in water if you powered it via a relay activated when you pressed the flush button
next point, in the pdf, you show a t fitting and two ball valves from the respective water sources. a simpler way would be to use a three way valve instead of the t fitting and eliminate the two other valves.
the three way valve would be the source selector, raw, or fresh.
just spitballing...

 

[Bmarler]

like dave says, install a backflow preventer in between the source valve and vented loop. those two things will keep you safe.
or, looking at the vacuflush water supply, there's a valve at the pedal, and the vent is behind the bowl. nothing complicated. if you wanted to mimic that, a solenoid valve in place of the backflow preventer would let in water if you powered it via a relay activated when you pressed the flush button
next point, in the pdf, you show a t fitting and two ball valves from the respective water sources. a simpler way would be to use a three way valve instead of the t fitting and eliminate the two other valves.
the three way valve would be the source selector, raw, or fresh.
just spitballing...

oops, should have read more thoroughly. i see the valve and preventer already in place...
only change i would make is to use the three way valve and only power the water supply(s) when flushing.

 

[Mac G]

Good idea on the three-way valve.
Then it would be physically impossible to have both sources incoming at same time as long as valve was operated correctly.

And good idea on switch to cut power to everything (solenoid) when not in use.

Thank you

 

[jleonard]

I converted an older Jabsco raw water head to fresh water. It was pretty easy.
I had already replaced one of the 2 in the boat with a Raritan Sea Era that was made for fresh water. It came with the backflow preventer and solenoid valve.
I simply bought the same components (not from Raritan) and plumbed the Jabsco the same way. I also removed the impeller from that section of the motor housing and plugged the 2 openings. That made it a very quiet flush.
(Then I removed all the thru hulls and glassed them up.)

 

[SteveK]

I have the raritan kit, quite simple to add onto the freshwater marine elegance.
Peggy, are you saying don't do it?

 

[HeadMistress]

Originally our toilets had a sea water flush, but after a technician told me that salt deposits could block the functioning I simply disconnected the water inlet of the toilet (to salt water) and connected a sweet water hose (simply split the shower hose).

That "technician" should stick things he actually knows something about. Yes, sea water minerals can block sanitation hoses, but it's simple to prevent: a cupful of distilled white vinegar flushed through the system weekly or last thing before you leave the boat each time.


Better yet see my post on Jan 5 detailing how to use the head sink to supply fresh water to the toilet to rinse all the sea water out of all the plumbing.



--Peggie

 

[HeadMistress]

I have the raritan kit, quite simple to add onto the freshwater marine elegance. Peggy, are you saying don't do it?

No I'm not. But it's notquite as to install as you think it is...First you'd need to add a remote intake pump to supply the sea water..then get the detailed instructions from Raritan tech support.


--Peggie