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Old 06-25-2016, 11:48 PM   #1
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Convert Groco k head salt to fresh?

I am close to buying a 1990 GB 32, and have a few questions about the head. I think it is original, Groco K electric that flushes to the holding tank. It leaks a bit and probably needs a rebuild. Do they still supply rebuild kits for this 25 year old unit?

Also, I would prefer freshwater flush to minimize odor. Can I convert this head to fresh or do I need to just buy a new, quieter toilet.?

Finally can I tap into the freshwater line in the head, or do I need to run a separate line to the freshwater tank?

Thanks for your help!
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Old 06-26-2016, 12:21 AM   #2
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IMO The Groco you have is a truely fine piece of equipment. Parts are availab le. To replace old school quality with new school globalist junk would be a mikstake. I dont see why changing the flush water source from raw water to house water would be a problem. A device that prevents back flow would be common sense.

Hopefully Peggy, the all knowing, will chime in here
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Old 06-26-2016, 03:47 AM   #3
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In case Peggie does not see this and chime in, as you put it, I will. Having just converted a raw water flushed toilet to fresh, having had to replace both toilet and holding tank macerator pumps, (not cheap), it is certainly a good way to reduce odours and prolong system life. But, and it is a big BUT. It is important that unless your Groco toilet has gravity flush only, (like at home), with a totally separate pump to fill the gravity tank, with no risk of any possible communication between flush water and the house potable water tanks and supply, it is not safe. If the same pump/impellor unit that macerates the waste is also doing the flushing, then the probability of bacterial contamination exists. If that is the case, as mine is, you have to use a totally separate tank and line to it, that does not even share a filling line. Bacteria can pass through even closed taps. Diverter valves, check-valves, and taps separating, are just not enough to guarantee dangerous contamination.

If I've left anything out, Peggie might well elucidate further. But having been in contact with Peggie, and receiving advice re this very issue just this last week, I felt I must comment, in case she does not see the OP's post, because his plan, while a worthy one, is fraught with danger unless he is aware...
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Old 06-26-2016, 08:18 AM   #4
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The repair kits are still available and the Groco K is still in production.

The only safe way to convert it to a fresh water flush is to install a dedicated water tank. PeterB did a good job of describing the dangers.

The Groco K is a terrific manual toilet but if you want fresh water flush, treat yourself to a Raritan Marine Elegance toilet. Your wife will thank you.

I like the idea of a fresh water flush. The Marine Elegance even comes in a version that allows you to choose fresh or raw water flush if you want to save fresh water.

You should buy Peggie Hall's book. An updated version was recently released.
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Old 06-26-2016, 08:53 AM   #5
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THe K is a masterpiece , not many heads will operate as well with onlt a replacement Joker valve , every so often.

The dangers of contaminating the Fresh water supply do exist.

Our technique is to use the shower hose to supply the flush water ,Aiming helps use less water .

Plan B might be a squirt bottle with a bit of Chlorox , after each use.

There are Mfd units that could supply the FW if you wish to plumb one in.
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Old 06-26-2016, 09:16 AM   #6
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I converted my head from salt to fresh water flush the easy way. I plumbed the head intake to the sink drain. When I want to flush I run the amount of water I want to flush into the sink then flush. This allows me to control the amount of water used in each flush and to extend the time it takes to fill the holding tank. There is zero chance of contaminating the fresh water supply this way. Note, I keep the sink drain seacock closed unless I am running a good deal of water into the sink for another reason.
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Old 06-26-2016, 09:54 AM   #7
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The Groco Model K is still in production. So yes, Groco still offers rebuild kits and parts for it. However, after 15-20 years, it's common for the Model K to begin to recirculate the flush because the piston bore wears beyond spec and the rings allow pressure to blow by. You could send the pump back to Groco to rebuild it and replace the bore housing but that would be expensive.

Also, I would prefer freshwater flush to minimize odor. Can I convert this head to fresh or do I need to just buy a new, quieter toilet.? Finally can I tap into the freshwater line in the head, or do I need to run a separate line to the freshwater tank?

NO!! Don't even THINK of doing either one! NO sea water toilet should ever be connected to the potable water supply and every toilet mfr specifically warns against it in their installation instructions. ONLY toilets that are specifically designed to use pressurized fresh water can safely be connected to the potable water supply.

So, taking the toilet's age and likelihood that it does recirculate into account along with your desire to use fresh water, I'd replace the toilet with one designed to use fresh water. The Raritan Marine Elegance is the top rated macerating electric toilet and is designed to use pressurized flush water. Raritan Marine Elegance Adding the "Sea Fresh" system to it, will even allow you to switch between fresh and sea water at will. Get a quote from Parks.

Amazon has the "updated, revised and expanded" 2nd edition of my book in both kindle and hard copy.
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/
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Old 06-27-2016, 10:08 AM   #8
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Greco toilet questions

Thanks to all--especially Peggie Hall--for your quick and useful responses.

Peggie, I just ordered your new book from Amazon. I'm looking forward to finally learning how to keep our new boat odor free!

Based on Peggie's suggestions (mostly) and on the Admirals esthetic issues with the old toilet, we will probably replace the Groco with a Sea Era electric salt-water flush toilet. It looks like a pretty easy replacement and we will just have to remember to dump some fresh water in at the end of each day's use.

What a great resource this and the GB Owners' forum is!

Thanks Again,
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Old 06-27-2016, 11:47 AM   #9
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we will probably replace the Groco with a Sea Era electric salt-water flush toilet. It looks like a pretty easy replacement...

It is...wiring is the critical part. You'll have to run a new dedicated circuit for it, on its own breaker, shared by nothing else, not even cabin lights, because anything that can reduce power to any electric motor will slowly destroy it. Low voltage is also one of the leading causes of sluggish discharge. And be sure to use the correct wire size for the distance from the battery to the toilet--which is always the ROUND TRIP distance. If wiring it is likely to be "above your pay grade" (anything electrical is above mine!), have a certified marine electrician do that much.

and we will just have to remember to dump some fresh water in at the end of each day's use.

That won't eliminate odors caused by sea water left to sit and stagnate in the INTAKE line pump and channel in the rim of the bowl because anything just added to the bowl only goes out the discharge...you're only rinsing out the toilet discharge line. If it's likely to be a real problem, consider going with the pressurized fresh water version instead unless you won't carry enough fresh water to spare any for toilet flushing.

If you have no choice but to go with the sea water version...When your copy of my new book arrives, you'll find a simple inexpensive solution on page 52.
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Old 06-28-2016, 07:19 AM   #10
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"we will probably replace the Groco"

List it on the for sale section , someone will want to rebuild it and operate another 25-30 years.
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