Vacuflush

M

mjmason1

New Member
Oct 19, 2013
533
Fall River, MA
Boat Info
1996 400 Sedan Bridge
Engines
3116ta Cats
I know this has probably been covered before, but, I have 2 vacuflush heads. Both hold water ok. The problem is the vacuflush pumps keep cycling every 20 minutes or so. Any advice?
 
The most likely culprit is the duckbill value. It is usually a DIY job as long as you have proper access.
 
mjmason1 said:
I know this has probably been covered before, but, I have 2 vacuflush heads. Both hold water ok. The problem is the vacuflush pumps keep cycling every 20 minutes or so. Any advice?
Click to expand...

Are your pumps seperate from the vacuum tank, or the VG2 system? If the latter, replacing all the duck bills is a project. I've recently done this job, and its not easy at all
 
Before you get too complicated though make sure you give both bowls a good inspection with the flusher ball valve in the open position. Sometimes 'non-flushables' get stuck in the back side of the ball valve, especially if you have had guests on board. You may get lucky with a simple toilet brush.


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The bowl seal can also cause the pump to cycle. I had that problem and simply cleaned the rubber seal as best I could and now its been fine for over a year now. I also bought a new seal for when it craps out for good - but haven't installed it yet.
 
The pump cycling is almost always the duckbills. The bowl seal leak will also lead to the pump cycling but it's also usually evidenced by the water getting slowly sucked past the seal and the bowl being empty of water. I've had both lead to a cycling pump. If you have water in the bowl and it stays there between flushes I'd start with the duckbills.
 
I am watching this thread with great interest. I had the same issue. Bowl would hold water just fine between flushes, but the pump would cycle on/off every so often. Replace the duckbills and still have the same problem. What is next?

Thanks,
Bennett
 
I have separate pumps for each head.

Had the cycling problem at different times on both heads.

1 head - scrubbing the ball in the bowl with the toilette brush solved the problem.

2nd head, required a seal kit in the head.

Duckbills are a pervasive problem - but also the worst job to fix. You might get lucky and solve the problem without going there.

Does anyone have any tips for diagnosing unit seals vs duckbills?

Mark
 
I have worked on my Vacuum system for years. Duckbill valves no matter how hard they are to change. I have a spare set on board always.
 
mjmason1 said:
Where are the duck bills? I have limited access to the vacuum mechanism.
Click to expand...

You have 4 total, 2 on either side of the pump.

bmac said:
The pump cycling is almost always the duckbills. The bowl seal leak will also lead to the pump cycling but it's also usually evidenced by the water getting slowly sucked past the seal and the bowl being empty of water. I've had both lead to a cycling pump. If you have water in the bowl and it stays there between flushes I'd start with the duckbills.
Click to expand...

Brian is spot on with this. If water remains in the bowl, the ball valve seal is good, and the problem is further up stream.

Other items to consider (although my money is on duckbill valves) is a vacuum leak. It is possible that hose clamp is broken or loose....or the vacuum pump is leaking internally (unlikely).
 
bbwhitejr said:
I am watching this thread with great interest. I had the same issue. Bowl would hold water just fine between flushes, but the pump would cycle on/off every so often. Replace the duckbills and still have the same problem. What is next?

Thanks,
Bennett
Click to expand...

did you replace all 4 valves?
 
I would do the bowl seals. I know, I totally understand the logic with the water level.
However, I bought a set of duckbills for mine 4 years ago, they are still unopened in the packet, and will remain so until I have to do them.
The bowl seals I do about every 8 months...
The sign is the pump cycling.
Sometimes the water level drops, sometimes it does not, either way it is a quick easy job to do it. And so far has worked every time.
I have replaced the complete kit once, valve and seal, etc,.
It is worth testing the bowl clamps to ensure they are tight and that the air is not leaking at that point.
When my system is right, I have no cycling, I can leave the boat for 4 weeks (unusual but has happened this year) go back down, flick the battery switch on and still have a full head of vacuum.
As I said all I have done thus far is regularly changed the bowl seals, when I hear the pump cycling, and sometimes there is no water loss from the bowl


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First thing everyone says - its the duckbills!

Sometimes that is the problem, but not always.

I have had a bowl that seemed to hold water - but still it was an issue in the head seals.

just saying - it might be the duckbills, but maybe not- but - if you search threads about vacuflush issues - the predominant response is "it must be the duckbills". that's the first response that always comes out.

In several years of boat ownership, with multiple vacuflush issues - have not had a duckbill issue yet.

probably the next issue it will be the duckbills.

Just saying - my 2 cents worth,

Mark
 
+1 on not always the bills. Easy first remedy is the bowl and then dig in deeper.


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I am going to try the seals. I can't get at my duck bills. They are midships under the guest bunks. You need to be young and skinny to get there.
 
mjmason1 said:
I am going to try the seals. I can't get at my duck bills. They are midships under the guest bunks. You need to be young and skinny to get there.
Click to expand...
Mike, I just put a post in 40 Sedan Bridge thread that might help you out should you need to do the duckbills.
 
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