Monomatic toilet

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Raven3633
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Joined: Mon Aug 24, 2020 6:41 pm

Monomatic toilet

Post by Raven3633 »

I have a boat 1973 F36 with a Monomatic toilet , I have no clue how it works. First issue for me is how do I get water to the toilet? I have hooked up all of the water lines and not one goes to the toilet. I do see a hand pump in the closet of the state room that seems to have the waterline that runs to the toilet attached to it, Do you manually pump water into the toilet? Also, when evacuating where is it going? I see that it can be set to evacuate overboard or to holding tank, how to I set that.?

Any information would be great. I have the boat nearly all dialed in but for that.

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prowlersfish
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Location: Lower Chesapeake Bay ,Va

Re: Monomatic toilet

Post by prowlersfish »

I Had One of those . First boat project I did was get rid of it . recirculating toilet ? not on my boat



"The Monomatic is a self contained recirculating toilet. It has an internal maserator and circulating pump. It needs a "charge" of a gallon or two of water with a preservative chemical added. They work a lot like and airplane toilet."
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MonomaticToiletManualPagesAllMAIN.jpg
MonomaticToiletManualPagesAllMAIN.jpg (108.92 KiB) Viewed 286 times
Boating is good for the soul
77/78 TROJAN F36 Conv.
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captainmaniac
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Re: Monomatic toilet

Post by captainmaniac »

Like Prowlersfish said, this is a recirculating system.

You will have an incoming water feed to the head that goes to the right hand side (looking at it from the front). Just to its left will be a vent fitting that goes out through a through-hull. You may (should) have a shutoff valve for the water feed, so need to open it when you want to prime the head then turn it back off afterwards. Plumbing to that infeed probably is just a carry on from the cold water line to your faucet in the head.

Here's a pic of what I used to have (replaced with a macerating unit a couple years back).
Head 1.jpg
Head 1.jpg (34.2 KiB) Viewed 283 times
How the system works:
  • The head needs to be 'primed' with 3-4 gallons of water. Open the valve and let water pump in until you don't hear the sound of 'bubbles' anymore.
  • That means the outlet end of the feed line is not just pouring more water in, but is now under water in the reservoir, so the reservoir is primed. [think: use a hose to fill a bucket with the end of the hose a few inches above the bottom of the bucket... lots of splashing / bubbles as things fill up, but once the end of the hose is under water it gets very quiet - THAT'S what you are looking for]
  • Once primed, the flush button on the back left section of the head can be used to pump / recirculate the water to 'flush' the system. Anything flushed goes into the local reservoir.
  • Pour in toilet chemical (liquid) to help deal with odours etc (google or your local marine supply place for the right stuff), or if powder dump it in the bowl and flush it through.
  • As you use the head, liquid and solid waste goes in to the local reservoir. When you flush, fluids (what was clean water + head chem + pee) is used to flush / rinse the bowl, solids remain below.
  • Once reservoir is full, or things smell too much, time to empty the head!
Now this part may line up or not... on my F32 my Monomatic was plumbed to a holding tank under the v-berth. I had a manual pump (crash pump) in a hanging locker, and when the recirc head itself was full I could use that pump to transfer contents to the holding tank. Once contents were transferred I could recharge the head with new fresh water + toilet chem, and repeat process. Could transfer it 4-5 times before I actually needed to get a pumpout.

Raven3633
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Joined: Mon Aug 24, 2020 6:41 pm

Re: Monomatic toilet

Post by Raven3633 »

Where I am not sure of is where the water line is coming in to the toilet. I opened the value on the right side of the toilet. I hooked up all of the water lines under the steps, on the line that seems to be running toward the head (5/8 line) I opened the stop cock and water pumped over the side of the boat out of one of the vent holes on the starboard side (head side). I do see the pump handle in the closet so I understand that to be where I pump the waste out. but I still do not know where the water is coming is.

Another question. How do I eliminate this toilet and simply install one that hooks directly to the water pump that I can install a T to make work.?

Raven3633
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Posts: 10
Joined: Mon Aug 24, 2020 6:41 pm

Re: Monomatic toilet

Post by Raven3633 »

There is also under the sink in the head what clearly is a pump and it appears to be running to the bottom of the toilet.

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