Vacuflush puzzle continues-gctid349598

[Guest]

I posted on this some months ago and have followed through on the excellent advice given, but to no avail.

Here is where we are at;

- Replaced all the duck bills in the pump.

- Replaced the rubber ring in the bowl and the plastic dome gizmo along with all of the other parts in a Sealand rebuild kit.

- Used a vacuum tester and established that when the pump runs for 30 seconds stops at 14.8 and does not lose anything no matter how long it is left (thank god because I cant open it again).

- Pull the test unit out and the pump runs perpetually so the issue is in the toilet itself. (Thankfully relatively easy to work on and clean)

So what else can it possibly be???

How else can I test?

The only thing that I have not replaced is the gasket between the floor and the toilet assembly but if that were leaking I am sure my vacuum tester would not have sealed and held vacuum on the outlet cone?

I am at my wits end.

Thanks

Wayne

[Guest]

Does the water level in the bowl drop or stay full?

[Guest]

Sure does

No loss. Hence the puzzle, where is the air coming from?

[Guest]

Stay full that is

[Guest]

What is the off time interval between the vacuum generator on cycles?

A pump spray bottle w/ a soapy solution is handy for locating a vacuum leak.

One possible leak location is where the waste hose from the bowl dumps into the vacuum generator. That connection is a slip fit with no clamp. Also check the O-rings on the vacuum switch and on the fitting for the drip tube. On mine I lube those w/ white lithium grease, not a recommendation.

The threaded fittings at the duckbill valves need to be snug, that is it. If those are too tight, then they can deform the duckbill valves, holding them open.

The rotating ball in the toilet needs to be clean for a good seal.

[Guest]

wingless wrote:
A pump spray bottle w/ a soapy solution is handy for locating a vacuum leak.

How does that work on a vacuum leak? There wouldn't be any bubbles to see.

wingless wrote:
One possible leak location is where the waste hose from the bowl dumps into the vacuum generator. That connection is a slip fit with no clamp. Also check the O-rings on the vacuum switch and on the fitting for the drip tube. On mine I lube those w/ white lithium grease, not a recommendation.

I don't think he has the small boat integrated unit you're familiar with. I think he has a separate pump, separate vacuum reservoir (multiples), etc.

wingless wrote:
The rotating ball in the toilet needs to be clean for a good seal.

He says he has replaced all the consumables there, but it sure sounds like the leak has to be in this region.

[Guest]

wingless wrote:
A pump spray bottle w/ a soapy solution is handy for locating a vacuum leak.

whiskywizard wrote:
How does that work on a vacuum leak? There wouldn't be any bubbles to see.

It has worked for me. A dry leak is silent. The addition of a liquid seals the leak, then makes a hissing noise.

wingless wrote:

whiskywizard wrote:
I don't think he has the small boat integrated unit you're familiar with. I think he has a separate pump, separate vacuum reservoir (multiples), etc.

My understanding is the vacuum generator is the same or similar for "integrated" where it is bolted to the top of the tank and detached. Regardless, the principal is the same.

[Guest]

Does the problem stop when the boat is moved to the northern hemisphere? If so, then it may be attributable to the Coriolis effect. This documentary film is a useful reference on that subject.

[Guest]

wingless wrote:
My understanding is the vacuum generator is the same or similar for "integrated" where it is bolted to the top of the tank and detached. Regardless, the principal is the same.

We need the OP to confirm this but I don't think he has one of the small boat systems. He'll likely have 1 S-series vacuum pump and 1 VT vacuum holding tank per toilet. There will not be any integrated vac tank/pump/holding tank at all. All separate components, and the only connections will be hose and pipebarbs with hose clamps, and the threaded duckbill collars.

[MerlinV]

When we initially purchased our last boat (2001 4087), both vacuflush heads had problems of almost continuous cycling. All of the seals were replaced throughout both systems, including duckbill valves, and the uniseals on top of vacuum generator, but the problem persisted.

In desperation I contacted SeaLand directly, who put me in touch with their local service dealer. During discussions with him, it was indicated that on certain vacuflush models between 1999 and 2001, there could be an issue with the porosity of the ceramic toilet bowl. My initial reaction was disbelief, but we finally replaced both toilet bowls, the problem was solved. The dealer offered me a deal at cost as the boat was only three years old at the time.

I was surprised to hear that even after checking with a tester, the unit continued to cycle without the problem area being identified. I found that it was really a systematic process of checking the toilet bowl first, then on to the vacuum generator. If the toilet itself, and all the duckbills hold the vacuum, then its on to the reservoir and the uniseal where the dip tube enters. It is hard to achieve a good seal there.

Once vacuum leaks are eliminated between the toilet bowl an vacuum generator tank, the only thing left is the pressure switch.

Fingers crossed, the vacuflush systems on our 490 have been trouble free and maintenance free for over three years now

[Guest]

We have a tool in our box at work called an ultrasonic leak tester. We use it on compressed air leaks and bearings. I know from experience that this think can hear a mosquito fart from 20 feet away. It only"hears" high frequency and a vacuum leak is that, all day long. We use a hose on the end of the unit and can find a leak within a 1/4" proximity. You should try renting one of these. If you have a leak, this little gizmo will find it. It has never let us down.

Good luck steve

[Guest]

pika steve wrote:
We have a tool in our box at work called an ultrasonic leak tester. We use it on compressed air leaks and bearings. I know from experience that this think can hear a mosquito fart from 20 feet away. It only"hears" high frequency and a vacuum leak is that, all day long. We use a hose on the end of the unit and can find a leak within a 1/4" proximity. You should try renting one of these. If you have a leak, this little gizmo will find it. It has never let us down.

Good luck steve

+1! Good suggestion, Steve! While I haven't used one of these to listen for mosquito farts, these units are worth their weight in gold! I used it to detect a leak in a refrigeration system and it was dead on accurate! I used a unit from a company called Visual Optics. It was purchased on eBay for something like $150 for a used one. I would highly recommend giving it a try.

[Guest]

Thank you for all of the input.

The pump is as shown in the photos is the one, but it is fine, as when I use the vacuum tester it creates perfect vacuum and stops. Does not lose any vacuum over an hour.

The issue is in the toilet end somewhere. Easier to get at but harder to diagnose.

There are 2 units on board, one is perfect, this one has not worked while I have owned it. I have progressively replaced everything, culminating in buying the vacuum gauge and establishing that it is at the toilet end. (Roberts suggestion as I recall).

I suspect one of those porous bowls but that is hard to test and prove.

Regards

Wayne

[Guest]

How about you swap toilets and see if the problem follows the toilet?

Cheers steve

[Guest]

Aussie wrote:
I suspect one of those porous bowls but that is hard to test and prove.

Smear it w/ Vaseline to seal the porosity.