Vacuflush... Blocked or Pump Vacuum?

Boat Guy

Well-Known Member
May 15, 2013
2,289
Who knows? Could be Cali, Oahu, Florida, Annapolis
Boat Info
400 DA
Engines
CAT 3116s
Ok, so on Memorial Day Weekend the forward head seems blocked...Thing is, since I only use it and I know how careful to be with waste / etc. I'm having a hard time believing it...

I'm willing to accept it...haha...But, I was wondering if the pump fails or doesn't activate, would it cause the same effect? I basically have water from what I think is the whole hose and half bowl...I tried plunging it to no avail...Is there an easy way to release vacuum to see if the pump works to rule out failure?

I called the local dealer and I expect to hear from them in about a week???? Maybe??

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***** Solutions / Diagnose - Vacuflush VG-2-12
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The Vacuflush VG2 is a relatively self contained system that is the flushing system between your head (toilet) and black-water holding tank.

It includes the vacuum pump, motor, pressure switch... The one picture shows the unit with the protective cover on. The cover is removed by unscrewing two small phillips head screws...It is simply a cover and will not open the system, nor release any waste or pressure.

Once the cover is removed you can see the parts easier. The motor is attached to the pump and the pressure switch is the switch that the power goes to.

The black negative lead goes directly to the motor and the red, positive, goes to the pressure switch.

If you want to test the motor you can simply jumper the two red leads on the pressure switch. If you do so, you should hear the motor and pump running and see the pump moving... NOTE - Only do it for a second or two or you could over-pressurize and potentially damage the system.

If it works, great, you know your motor is operating.

Next, you can loosen the worm clamp / hose clamp surrounding the pressure switch and once loose slowly pull the pressure switch out just enough to hear if pressure is being released...If you hear it, continue to release pressure to see if the pressure switch is working...If it's working, once the vacuum gets low enough the switch will activate and the motor will start.

If it activates and it pumps, and it stops pumping, then you pretty much know the system is functioning and if your head (toilet) is not flushing, you have a blockage...

Where, I don't know....But at least you've ruled out no vacuum.
 

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Thanks Marty, your idea helped... Added notes to my first post.

It seems my system is fully functional.

When I bypassed the vacuum switch the motor and pump worked. When I released some vacuum by loosening the switch from the housing the system started and built up vacuum again...

So, I guess I have a blockage somewhere...
 
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I usually start by turning off water. Find a wooden rod what won't scratch and is about 1/2 diameter and 16-18 inches long. Depress foot valve and push rod to base bottom 3/4" opening where everything exits to see if that's where obstruction is. Also 3/4 garden hose and city water pressure applied has worked for me. Sure better than pulling stool
 
Good idea, but tried that...When I flushed the last time it was just fluid and it all disappeared. Meaning the block happened in the prior flush and the system built up vacuum. It also took awhile for the est. 25' (?) hose to fill, which I did to see if I could use a plunger carefully and release it...The block seems to be very near the system...If I had a small drain snake, I would try that...I put a little blue West Marine holding tank cleaner down but I don't think it's actually getting to the clog.

I understand "duckbills" (?) can block the system, but I'm not sure how...
 
The duckbills are one way valves, that are made of rubber and look a bit like duck bills.... they are what makes the system work - if your system builds and holds vacuum, they are most likely fine. Be very careful using plungers on vacuflush systems as the action of a plunger can invert a duckbill and ruin it. Be very careful with a drain snake also, if it runs into a duckbill it’s likely to damage it.

Unfortunately, it sounds like you are in for a real nasty job, buy a cheap wetvac to suck as much water out of the system as you can, and to progressively clean up as you go, I’d say start by uncoupling the plumbing where it joins the vacuum generator, there is often several 90 degree elbows close to that, where blockages are most likely. Working this way (away from the duckbill) it’s fine to use drain snakes etc, also at this point you can use a plunger in the bowl as it’s not fighting vacuum and can’t damage a duckbill...) once you have cleared the blockage, reconnected the plumbing and cleaned up all the spilled Blackwater, put the wetvac in the bin...
 
Thanks, I was thinking mostly the same...I'm just not sure where the first duckbill is from the forward head. Are there any before the hose connects to the elbow at the vacuum generator?

It seems the duckbills are after that coupling and inside the generator, no? I'm looking for a schematic or drawing...
 
I always try and complete my threads with useful information so if people search, hopefully it will save them time.

To determine if your system is operational, see post #1

If you've determined you have a clog, from what I've been told, usually the clog is in the small opening under the toilet bowl...Which means, perhaps the best way to clear it is either with a 20"- 1/2" diameter stick or something and push it through. Or, turn off the system and use something to try and pull it out instead of it potentially getting sucked down and clogging somewhere else...

My clogs have never been at that location...Always further down the line...I usually have luck using a small plunger and without too much force (though not too little) plunging about 100x making sure I get a little suction on the up side too so that it's a bit push/pull....

WARNING - I've been told using a plunger could potentially damage the duckbills and if you use to much "pull" you might invert them.... I've never experienced this...Though, I am a bit careful...In fact, if the first 100x doesn't work I usually let it sit for hours and try again....Repeat...

Well, this time, even the repeat didn't work so I figured something must really be wrong...

Plan B - Drain Snake -

I bought this one:

https://www.homedepot.com/p/RIDGID-KwikSpin-1-4-in-x-25-ft-Auger-57038/303644603

Apparently the reviews are bad and it says not for use with toilets .....haha..go figure...

Though, our toilet system is smaller than the ave. home system and I wanted something small that wouldn't get stuck...Rather have Plan C (Hire someone) than get the auger stuck and not be able to pressurize the fresh water system because I can't close the toilet ball valve...That would suck...

Anyway, to do this I shut off the fresh water system, opened some faucets to depressurize and drain the water (so no more water goes into the toilet bowl when you hold down the lever to expose the opening)...Once done, with rubber glove (advised) I pushed the flush lever down and kept it open, then push the snake carefully down the opening until I felt it blocked...Then turned the auger and see if it clears it....It didn't, so I'd pulled it out and investigated the end...There was gunk (you know what I mean) around the tip. So, I cleaned it, and reinsert...repeat...once I did it the second time it cleared and the vacuum took all the water in the toilet bowl...

I hope this helps someone...

BTW - I also recommend filling the bowl back up a few times with some fresh water and maybe some cleaner to do a few flushes before reuse....

NOTE: If you recall in my first post, I did call and left a message at the local dealer...I know it's a holiday weekend, but I never heard from them...I guess they will call sometime this week.
 
Thanks, I was thinking mostly the same...I'm just not sure where the first duckbill is from the forward head. Are there any before the hose connects to the elbow at the vacuum generator?

It seems the duckbills are after that coupling and inside the generator, no? I'm looking for a schematic or drawing...

The duckbills are inside the pump unit.
 
When working on Vacuflush systems, keep in mind a few things:

1. Nature abhors a vacuum.
2. Fluids flow from High Pressure to Low pressure unless work is supplied.
3. The Duckbills are essentially check-valves to prevent back-flow.
4. The Vacuum Generator creates the vacuum against the ball valve seal in the bottom of the bowl.

Jaybeaux
 
Had the same issue on my port head. Turned out to be leak in main vacuums like between vacuumed generator and the head. The big line that runs under the salon floor and in to the engine bilge are. Messy job.
Also rebuilt the vacuum generators. Found a few minor vacuums leaks.
I started flushing some vintage down the heads. Kind of treats the rubber components of the system. Down side is that for a while the boat smells like an over done salad. But I found the waste system worked great.
 

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