Holding tank Volcano!

dtfeld

dtfeld

Water Contrails
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Jun 5, 2016
5,571
Milton, GA
Boat Info
410 Sundancer
2001
12" Axiom and 9" Axiom+ MFD
Engines
Cat 3126 V-Drives
Went to pump out today, and as soon as the deck fill was off, several gallons of poopy sludge gushed out vertically and all down the side of the boat!!! It was a poopy volcano! The admiral wasn’t pleased!

Once it stopped surging out...I washed up and tried to fill and pump out several times. The pump out drew a vacuum against the tank, and refilling was only a couple of gallons, before the water backed up to the deck fill. I think the vent is clogged amoung other things. The good news is the empty light is now working!!!! Now if I can get the 1/2 and full to start working.

Now the front head doesn’t suck down at all (not clogged). It has always been the weaker head. Were the rear give a spirited whoosh...the front had been weak all this year.

Any ideas on were to start diagnosis? Is there a breaker or fuse on each pump? I don’t hear the pumps running.

Oh the joy!
 
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It sounds like you're getting a vacuum lock on the tank when pumping out. I would think that if it got up that high and out of the tank that it also clogged the vent filter. Might start there but I would replace it with a very short hose and see if you can pump out better. It sounds like you're getting a vacuum lock on the tank when pumping out.

-Kevin
 
Oh, and as far as the lights you are probably going to have to pull the sensor and clean it.

-Kevin
 
When you pump out, hold one of the pedals down and let the head be the vent for the pump out if you can’t empty it. With the head open, you should get a good pump out. You should have a 12v breaker for each head/pump.

Bennett
 
Your tank was overfilled, the vent filter stopped up. If you keep flushing, you are building pressure in the tank. You opened the cap and the pressure pushed "it" out. Clean vent lines and replace filter, you should be got to go, no pun intended.
 
Like others have suggested, at some point your tank has been overfilled, which blocks the vent filter.

More worrying though, is that there should be a relief valve in the very top of the tank, that is supposed to stop the tank holding pressure or vacuum in the event of a vent filter failure - the main holding tank should never hold pressure or vacuum, either condition can rupture it (with horrible consequences...)

The main holding tank pressurising is what is causing weak flushing of your heads, the vacuum generator has to fight the pressure..... the front not flushing could be that the excess pressure has caused a duckbill to invert.

Time for you to get to know your system better.... find and free the relief valve (or replace) re-lace he vent and clear the lines, get the model number off your vacuum generator and get new duckbills to rebuild it.
 
I need to dig into this...that tank is buried up under the port side behind the port engine...any advice on access?
 
Looks like this system has a pump out with a seacock. I have a discharge pump switch on the panel, but none of that seems to work.

Close the sea cock ?
 
My system has two vacumm generators, and what looks like a small holding tank connected to the aft head. Aft head is working, forward is not. Is it ok to use the aft head until I get the main system working?

Also, does the main vacumm pull waste from the afthead/smaller tank?
 
Slow down a second and learn how the system works before you do anything else. Each head has a vacuum generator which pulls from the toilet and pushes to the holding tank. They are independant of one another. There are two pump out methods from the holding tank. One is to suck it out from the fitting at the top of the side deck. The other is to use the macerator to grind it up and push it out through a thru hull. Read your manual to understand how to use the macerator. But it can only be used three miles offshore. There is a valve at the tank pumpout output right at the bottom of the tank. It will close off both the macerator and shore pumpout path. Make sure that valve is open when you pumpout using either method.
 
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Spent more time in the manuals than on the boat. Unfortunately, manuals are very basic. Not a whole lot of help especially for this system. Plus everthing is buried making getting to any of it a pain. The dometic site much more helpful, but haven't found good description of dual pump system

I assume the aft vacuum pulls into a small holding tank, and the other vacuum pulls it across into main holding tank? So if the main tank is not working, the whole system is down?

My guess is the vent filter has not been changed in a long long time. It's on the outside of the tank where I can barely get finger tips on it.

Sea cock is buried outboard and behind the outer stringer, tried to access from behind engines...no way.

Gonna have to pull the vacuum pump and start digging but it'll be next week once the ladies are gone
 
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David,

On my '03 410, the vent filter was on top of the aft portion of the holding tank. You make a pretzel out of yourself and get behind the port engine and it is easy to replace it. It is held in by a plastic clip and plastic strap that may or may not need a small screwdriver to pop up and release. Take a pair of channel locks with you for the end fittings. Also, the transom shower hose lays on top of the filter when it is stowed, so open up the door and pull the hose to its full length before your crawl in! At 71, crawling out from behind the engines was the most "fun" part!!! Oh - don't get a charlie horse while you are back there either!! Ask me how I know!

As Bill ZZ13 said, you have to open the seacock to enable the circuit on the macerator - and be three miles offshore. Close the handle and remove it (or zip tie it closed) when you are inside of three miles
 
Given your location, this may have a simple cause and solution……"dirt dobbers" love to build nests in the vent fitting. Check and clear the holes in the vent fitting if they are blocked.
 
If you are ready to call in the expert, contact Robbie at Robbie's Marine service, he is the go to guy on Lanier for marine head issues. 770-271-2470. Hope it is easy as changing vent filter and clearing lines but if you get stuck call him, very reasonable.
 
Howdy gents!

Just got home, awsome spring break trip!!! Not without issues, but we made it out and about and made some family memories! Great weather. I'll have to post up some pictures of our adventures.

Heading back down Thursday and will dig into the head. Gonna build a filter (actually 2) and move it to where I can get to it and easily change out. I think a set of duck bills and a diapham ought to sort the rest of it out. +1 Frank on mud dobbers. I may replace the entire vent line while there, and per Carter, the positive pressure relief valve.

I'll have a brand new system!
 
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dtfeld said:
Thanks Carter!
Click to expand...


interesting....do all holding tanks have this relief valve?.....I have worked on my waste system several times and I don't recall seeing a valve like this on my holding tank.....I would assume it is located on top of the tank....correct?....

cliff
 
Here's the diagram from the 410. I'm guessing the whole vent system is clogged up from overfilling.
Head.PNG
 
Hold the phone...a couple photots I snapped for remote diagnosis purposes. This is a "T" style or discharge pump where a vacumm generator is supposed to be installed...might this explain the lousy performance of the front head? Will it work? At least for a while?

Vacumm Generator.jpg
Head Pump.jpg
 
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