Strange problem H-N-T PuraSan problem

[Billylll]

For the last 18 months I have had intermitant problems with my H-N-T/ PuraSan set up. I finally resolved it but I wanted to pass this on in case anyone ever has this problem. About 18 months ago it appears something solid got flushed and I never was told about it. Here is the set up ME freshwater head, dumps directly into a newer Poly 36 gallon holding tank. Out of the tank is a Y valve one side goes to the deck pumpout the other went to a Macerator pump that is controlled by a Raritan Hold-N-Treat into a PuraSan. The PuraSan went into a vented loop to a under the hull throughhull. When not in an NDZ the PuraSan would build pressure and not allow the proper transfer of effluent and the tablet dispenser wouldn't always adjust to the fill line it would often overfill. I must have replaced 3 of the junk Jabsco macerator pumps. My plumbing is all 1" on the PuraSan. Finally I thought it might be back pressure from the below the water through hull even though it worked well the 1st year and a half. I installed a new throughhull just above the waterline on the side of the boat. Guess what someone flushed a soda bottle cap it got caught in the outlet adapter inside the 1" discharge sanitation hose between the outlet and the vented loop. It would intemitently flip from closed to half open. Sometimes when I opened the mixer cap I would get sprayed with effluent (yuk) then I would have to do major clean up work inside the vanity under the sink where the PuraSan is located. I only found this after replacing the pump with a high quality SeaLand diaphram pump and the duckbills kept turning themselves inside out with the same backpresure problem in fact it was worse with the SeaLand diaphram pump. Needless to say I hope this never happens to anyone else and if your PuraSan has major back pressure check for obstructions on the discharge side of the unit especially if your discharge sanitation hoses are 1"!
Man am I happy to have upgraded everything but it was very frustrating finding the culprit.
Bill

 

[Radioactive]

Bill, you make an important point:

As boaters, we "expect" to find such things as corroded grounds, leaks ( from dern near everything ), as well as vibration issues. However, these root causes represent only about 70% or so of the causes. Sometimes, you need to think outside of "The Box". It is a completely different way of looking at things, and you can come up with a whole pile of wrong hypotheses, but sometimes, that is the way to do it. Either that, or a complete "breakdown and rebuild".

The other thing is that we, even as boaters, tend to forget that, unlike land based sanitation systems, a marine sanitation system will not "eat everything you throw into it", and is quite finicky. This one item is why so many boaters are true experts at the assembly/disassembly of MSDs...

Thanks for the "head"s up!

 

[Billylll]

It's never fun working on the MSD system or head in a boat. I was relieved to finally find the soda cap problem. How it got there is another story? I can't see it getting past the ME head but perhaps it was when I had the VacuFlush head which doesn't macerate? I just know for the last 18 months when I used the MSD the problem seemed to come and go but recently it almost never worked properly. That was because the cap that was lodged and dislodged had calcium and some effluent build up and was growing in size. Take a bottle cap and place it inside a right angle 1" adapter when it is in the right position it is like having a check valve closed. I imagine because of the vented loop it got caught between the right angle 1" adapter? I also had a few small pieces of the old Jabsco macerator's impellers in the same elbow behind the bottlecap. My other idea was somehow this wasn't flushed and worked it's way backward through the throughhull? Perhaps when I had the bottom done a cap as used with tape to close off the throughhull? However that really makes no sense to me at all, I still think a guest flushed something after it was dropped and somehow it made it a long way or possibly when winterizing the MSD the cap was dropped into the mixer? The real mystery to me is how a cap made it that far without damaging the internals in the PuraSan (it didn't) I had it apart as well. Most of the caps edges were missing it was like an oversized Nickle (5 cent piece) coated with crap and calcium lodged that would swing like a check valve.
Bill

 

[BarrenRiver]

Bill if the bottle cap was still fully intact I don't see how it could pass thru the Purasan...I don't think there is enough room for a bottle cap to pass up and over the chamber...and besides the macerators blades from the ME & Purasan would have cut the hell out of it

I had the same thing happen only at the other end once..had a houseboat which had an Atlantes head which wouldnt pump any water....crawled down into the hull of a really nice houseboat to find a jungle of duct work, after getting to the stand pipe, (which was a job in itself becuase of the duct) and removing the hose from the strainer I blew back and could hear it bubbling under the boat, so no clogged stand pipe..hose back on and crawl back out to get a water pump....crawl back in, install the new pump, crawl back out, and flush the head and the same thing, no water....crawl back in to check the strainer and nake sure its sealed...tighten everything up and all looks good,,,,crawl back out and same thing no water....what the f&*k...this is the second job of the day and by then I am tired of crawling in and out of hulls...so, go home and plumb up a new strainer and will change it it the next day...next day crawl in and change out the strainer...crawl out, and its the same thing, no water..so I crawl back in and start taking things apart...there was a ball valve just before the strainer, when I took it off and looked thru, couldn't see it open, pecked it on the floor and out falls a small walnut, which had been sucked up thru the stand pipe and lodged in the ball valve shutting off the water...when I blew down the hose it would let the air pass but couldnt blow it out of the stand pipe...hooked it all back up and all was well