Vacu flush problems

Afternoon all,We just purchased a 1989 GB36 EU.Its a nagging problem that even the hired experts can't find.The Vacu flush system is still expelling black water through the air vent,even after two full pumpouts.this system has a
three way switch next to the system in the E/R.This switch says empty.off and fill.The vacu flush power is connected to the maserator switch on the main panel.It operates normally but the discharge goes out through the air vent,
and to use the maserator for overboard discharge of which we dont do,
you need to open the main discharge valve and put the switch in the E/R
to empty,if turned to the off position it shuts off the maserator,and if turned to the fill position it turns it back on.Any ideas why it still pumps out of the air vent and not into the holding tank.

Welcome aboard. Peggie will probably chip in on this problem.

vacu flush problems but no responces yet

still have no answers

do you have an inline vent filter? Mine has what appears to be garden hose connections. If you have those maybe try reverse flushing, or at least loosen/remove to see if the vent line is under pressure.
what you describe still sounds like a full holding tank. Flush has nowhere to go but out the vent line.

Some pictures of the internal plumbing and the system would help a lot. Is your system one of those with an integrated holding tank:




or a separate one built into the boat?


It doesn't sound like you have hired any "experts", that's for sure. But I would have to see it. It "sounds" like someone mis-plumbed the vent.

Peggie will probably chip in on this problem.

Yup...I'm like a fire horse smelling smoke when someone posts a potty problem!



H WillI ! I see you've just joined our merry band..welcome aboard!

The Vacu flush system is still expelling black water through the air vent,even after two full pumpouts

It's the HOLDING tank, which isn't a part of the VF system, that's expelling waste out the vent, which is a good indication that your tank is overfull. And it has to be both full and highly pressurized to do that because what you've described is a good indication that the vent is at least 90% blocked, preventing the pumpout from pulling out more than a gallon or two. So although you've been to a pumpout twice, your tank is still mostly full.

All tank vents have two main functions: to provide an escape for air displaced by incoming contents and provide a source of air to replace contents as they're pulled out. When air displaced by incoming waste cannot escape out the vent the tank becomes pressurized, creating increasing back pressure that prevents the toilet from flushing.

Without a source of air to replace contents as they're being sucked out of the tank, the pump will pull a vacuum that'll prevent it from pulling out more than a gallon or two. A particularly strong pumpout can even implode a tank.

When air displaced by incoming waste cannot escape out the vent the tank becomes pressurized, creating increasing back pressure that prevents the toilet from flushing.

Do NOT use the toilet again or try to pump out or dump the tank until you've cleared the vent. Without a source of air to replace contents as they're being sucked out of the tank, the pump will pull a vacuum that'll prevent it from pulling out more than a gallon or two. A particularly strong pumpout can even implode a tank.

99% of tank vent blockages are the vent thru-hull and the other end of the vent line--that end of the hose and the vent fitting on the tank. Start by cleaning out the thru-hull...use a screwdriver blade, ice pick--whatever works. If that doesn't result in a spew out the vent, you'll need to relieve the pressure before removing the vent line from the tank to clean them out...so open the deck pumpout fitting VERY CAREFULLY with a hose at the ready. Be sure you're UPwind of it! Scrape out that end of the vent line and the vent fitting on the tank...replace the vent line.

If there's a filter in the vent line, remove it...once a filter gets wet--which can happen when a tank is overfilled, the charcoal swells and blocks the vent.

That you're including the holding tank and its vent in the VacuFlush system doesn't sound like you really understand how a VacuFlush toilet system works either....you're not alone! Which is why I've written a piece I call "VacuFlush 101" that I'll be glad to to send you (and anyone else who wants it) if you'll send me a PM that includes your email address (no way to attach anything to a PM). I'll also be to help you sort what you need to do to solve this problem and prevent it from happening again.

And I just realized that the system here won't allow newbies to include email addresses in PMs till they've been here long enough to demonstrate they aren't spammers. So I'll send you a PM that includes MY email address...if you use it, I'll attach the info to a reply.

--Peggie

Thanks all of you for your responses,Ive taken everything apart and found every thing in working order,this system had a diaphram waste pump going from the holding tank to the discharge thruhull fitting.I found the diaphram to be cracked,so I replaced this with a new maserator pump,tested it and it works great,tank is empty,from previous pump out.the vent from the holding tank was clear at both ends.The vent from the top of the holding tank goes out at a thru hull at the water line,and has no loop,straight from the tank and down three feet to the water line?Could this be my problem,She still pumps waste.and why is there a separate switch to use the maserator,its by the discharge line and has three settings.empty-off and fill.when turned to empty the maserator works.And thanks Peggie ,will get your book

Will knot said:

The Vacu flush system is still expelling black water through the air vent,even after two full pumpouts.............

..........the vent from the holding tank was clear at both ends.The vent from the top of the holding tank goes out at a thru hull at the water line,and has no loop,straight from the tank and down three feet to the water line?Could this be my problem,She still pumps waste.and .............

Click to expand...

still pumps waste?
Are you by chance speaking of the vent at the top of the 'U' anti siphon discharge hose is still leaking sewage?

The only vent line on this system is on top of the holding tank,there is no loop in this line and it drops down to thewater line thruhull,not having a loop may be our problem.
when you flush the head the vacu flush pumps it into its own tank and I think with this much pressure it goes up the vent and out,my prognosis?

and why is there a separate switch to use the maserator,its by the discharge line and has three settings.empty-off and fill.when turned to empty the maserator works

Several things you said--including a reference to what seems to be TWO vent lines from different tanks:

the vent from the holding tank was clear at both ends.The vent from the top of the holding tank goes out at a thru hull at the water line,and has no loop,straight from the tank and down three feet to the water line
--lead me to wonder if you have TWO holding tanks--a combination 9 gallon holding tank/treatment device called the TDX AND another larger holding that the TDX dumps into...the overboard discharge pump dumps the larger tank. (and btw, that route for for the vent from the top of the tank is not what it should be!)

A big clue for that would be a panel somewhere (that may or may not still be working) that has switches for "treat & hold," "treat & discharge" along with a really basic tank level indicator.



--Peggie

Hello Peggie,there is an acumulation tank that the vacu flush is attached to and it
then goes to the bigger holding tank,which has the only vent on top.there are no
other switches and no tank gauge,I have installed a Gobios tank gauge and it shows empty?All of the threads I have seen talk about a vent loop of which there is none.
On the main breaker panel there is a switch marked maserator,when using the head
this has to be on for the vacu flush to operate,but this wont operate the maserator
unless the thruhull discharge valve is open and the switch marked empty by the discharge line is turned to the on position.

Will knot said:

Thanks all of you for your responses,Ive taken everything apart and found every thing in working order,this system had a diaphram waste pump going from the holding tank to the discharge thruhull fitting.I found the diaphram to be cracked,so I replaced this with a new maserator pump,tested it and it works great,tank is empty,from previous pump out.the vent from the holding tank was clear at both ends.The vent from the top of the holding tank goes out at a thru hull at the water line,and has no loop,straight from the tank and down three feet to the water line?Could this be my problem,She still pumps waste.and why is there a separate switch to use the maserator,its by the discharge line and has three settings.empty-off and fill.when turned to empty the maserator works.And thanks Peggie ,will get your book

Click to expand...

If the diaphragm is cracked and the pump is a Sealand/Dometic T pump, I would replace the diaphragm and duck bill's and keep it for a spare or sell it on eBay. They are a fairly expensive pump.

If you replaced the T pump with a grinder macerator, I would put the T pump back in after refurbishing it. The T pump is a lot more powerful, pumps faster and can be run dry. The macerator can not be run dry and pumps pretty slow.

Will, does your "accumulator" tank look anything like the one in this drawing?

--Peggie

(Sorry about the size of the image...it's NOT a thumbnail!)

Morning Peggie,that is not the type we have,I am attempting to send some pics,

Accumulator like this?

Hello SYJOS no that is not it I am attempting to send some pics

We tried to send some pics via email to TF support but nothing back,silly
how do we send pics to our threads!

One last thought,if I added a loop vent above my vent discharge line could this solve
our waste problem?

Will knot said:

We tried to send some pics via email to TF support but nothing back,silly
how do we send pics to our threads!

Click to expand...

did you "Go Advanced" in the reply, it is button at bottom. Then click on the paperclip symbol and choose file.

The mtn picture one wants a web page address I suppose would work with dropbox or?

Thanks Soo-Valley

If you scroll down after you "go advanced" you'll see a box that says "Attach files"...in it you'll see "manage attachments"..click on it. That'll take you to screen where you can search files on your computer ("browse") click on the one you want to upload, then find the little box at the lower right "upload." when you've done that your photo should appear in your post.



--Peggie

Thanks Peggie

vacu flush problems

Pictures of our system

Holy mackeral that's a whole big lot of equipment and connections and points of failure just to flush a toilet. Safe the space, ditch that Vaculflush and get an electric Marina Elegance toilet. Two hoses, a fresh-water supply hose, a discharge hose, and a push button to send the poop on its way. Low maintenance and refreshingly easy to service every 5 or 10 years.

Will knot said:

Pictures of our system

Click to expand...

Amen! That's the most over-engineered mess I've seen in a long time! In fact I may add those photos to my "Onboard Chernobyls" file!

A VacuFlush system consists of only 3 components: bowl assembly, vacuum tank and vacuum pump. (The vaccuum tank and pump were originally two separate items...later versions combine 'em into a "vacuum generator.") The holding tank is NOT a part of the VF...the vacuum pump pushes waste to it while it re-establishes vacuum in the VF. There may or may not be a pump in the HOLDING tank discharge line to dump the tank at sea.

That's it--the entire VF system plus holding tank. I have no idea why all the other contraptions in your photos are there...what their purpose is. If it were my boat, I'd get rid of everything that isn't a part of the VF as it's designed. Once you've done that, at least 90% of your problems with it should disappear. If they don't, it may be time to consider Catalina Jack's suggestion!

I sent you a PM (private message) that includes my email address (the system won't allow new members to include email or links in PMs till they've posted enough times to demonstrated they aren't spammers) offering to send you my "VacuFlush 101" piece that explains how it works and how to maintain it. You'd only joined us day or two before, so you may not have known what PMs are. My offer remains open (to you and anyone else who'd like to send me a PM that includes your email address).

--Peggie

I was asked to post an illustration of a complete VacuFlush system. This schematic drawing shows the original 3 component system plus a holding tank and all the other options AFTER the VF. Newer versions combine the vacuum pump and vacuum tank into a "vacuum generator"...you can see a whole bunch of photos and schematic drawings of vacuum generators here:
https://www.google.com/search?q=vac...kAhUPIKwKHcxqDZEQsAR6BAgEEAE&biw=1079&bih=767

Thanks Peggie,Ive become quite familiar with the system,the one we have has the tank combination,not like your diagram but my main question is wether I should put a
loop in the vent line as it is at the water line and straight to the holding tank.We just bought this vessel,our previous one had the type in your diagram,never any problems
and it had a vent well above the water line

Will knot said:

Thanks Peggie,Ive become quite familiar with the system,the one we have has the tank combination,not like your diagram but my main question is wether I should put a
loop in the vent line as it is at the water line and straight to the holding tank.We just bought this vessel,our previous one had the type in your diagram,never any problems
and it had a vent well above the water line

Click to expand...

my guess will be no, it is a vent to exterior.
On the schematic Peggy sent the vented loop vent is on the discharge line, what I do not see in your pictures. also where is the sewage leak in the vent line that still continues?

Your system also appears to have quit a bit of stuff that doesn't belong in a correctly installed VF system and holding tank, including what you referred to as an "accumulator tank" between the vacuum genrator and the holding tank.


but my main question is wether I should put a loop in the vent line as it is at the water line and straight to the holding tank.

Absolutely not! The vent line needs to be as short, straight and as horizontal as possible, and completely open...which requires installing a new thru-hull on the hull at least as high as the top of the tank. The "vent" thru-hull should be replaced with an open bulkhead or "mushroom" thru-hull that permits free exchange of air with the gasses in the tank--essential to odor prevention and also makes it possible to prevent vent line blockages by putting a hose nozzle against to back flush the vent line every time you wash the boat and/or pump out. Both of these reasons require getting rid of the vent line filter...which actually helps to create the problem it's sold to solve.

--Peggie

Hello Peggie,sorry there is no accumulater tank its the generator tank with the VF ON TOP.
I pretty well realize there was another system on this vessel before this one.So you think
I should install the vent well above the water line with a new thru hull fitting? I really
appreciate your expert advise and all the rest of those who contributed.:Lifes a beach and then you go to sea"