Vacuflush advice needed - doesn't hold vacuum

[bobk]

I need some advice on where to look for a vacuum leak on the vacuflush. The leak is a strange one and I need to set the stage for the problem.

Back in the spring, a friend flushed a paper towell that took a few weeks to jam up the system. Prior to that it was working fine. After retrieving the paper towell, and replacing the bellows (the crank was shot) and the intake side duckbills, it seemed to be ok for a couple of months. After that it began to lose vacuum. The pump cycled about once per hour initially and then the frequesncy increased to 10-15 minutes. I tightened hoses etc to no avail.

But here is the interesting part. We left the boat for several days and shut down the vacuflush. When we returned and turned on the pump, it held vacuum for better than an hour before the toilet was used, and then began cycling every 10 minutes again. I got a couple more duckbills planning to change the discharge side, but before I got to the job, we again left the boat for three days, and on returning, activated the system and it again held vacuum for more than 1.5 hours before it ws used and then started tro cycle every ten minutes after the first use.

So the question is, where do I look for a leak that gets better after shutting the system down for a few days? Any and all guidance would be appreciated.

Bob

 

[bobk]

P.S. my system has three toilets, three pumps and vacuum tanks, but no vacuum gages so I can't verify the vacuum. However when it cycles, it only takes a very short time to shut off as opposed to the normal time following a flush.

Bob

 

[Pascal]

if you turn off noisy stuff (air cons, etc... ) you can usually hear a vac leak. check at the base of the head, some VF have a soft gasket that can get damaged if overtightened.

if you dont' hear a leak, I'd bet on the duckbills... sometimes they dont' seat themself very well, open them up and try to reinstall them again

 

[Brian Degulis]

Maybe it's not a leak at all could it be that your vacum switch is simply set to high or trying to hold to much vacum? If that's not it then you have a leak that's only present at higher vacum levels you should look for it right after the pump cycles.

Brian

 

[egaito]

My guess is the bowl seal, if the bowl is losing it's water with the leak. There's a kit for the flush "ball" and the rubber seal. The seal can get deposits on it over time. First thing I would try is to clean the bowl seal as best you can and generously apply silicone lube.

If the bowl isn't losing water, the vacuum switch can fail in such a way that it leaks vacuum....mine did.

If you can't hear the hiss with everything shut off, try pouring some water over the joints. It's a vacuum, so it doesn't blow bubbles, but it does tend to amplify the sound a bit.

 

[bobk]

Thanks guys. I've considered and ruled out most of the ideas.

1, The bowl holds water just fine so that seal is not the culprit.

2, All four duckbills were replaced recently. Two on the intake side were replaced in April, the two on the discharge side were replaced yesterday. I also opened the two from April and cleaned and reseated them with a bit of silicone grease to insure they went in right. I cranked pretty hard on these connections too.

3, The vacuum switch setting is probably not the issue as the system will leak all the way down overnight, not just to a lower vacuum. I reduced it a bit (no gage so amount not known) and the pump run frequency did not change.

A leak at the vacuum switch could be a possibility and I'll try to l;isten for it. Any other way to check it?

BUT, none of this seems to account for the observation that if the system is turned off for a few days, the leak stops or slows to at most about one quarter of what it was. What could account for that? It sounds like distortion of a seal due to the vacuum.?

Any other thoughts?

Bob

 

[Pascal]

don't crank the connections too hard, that will twist up the duck bills. Loosen them up, turn on the pump and tightenen them up till you no longer hear them leaking...

i don't know what kind of vac switch you have, but even though mine appear to be adjustable, they are not. that wheel dens't affect anything, afaik VF are designed not to allow vacuum adjustments.

 

[egaito]

A leak at the vacuum switch could be a possibility and I'll try to l;isten for it. Any other way to check it?

BUT, none of this seems to account for the observation that if the system is turned off for a few days, the leak stops or slows to at most about one quarter of what it was. What could account for that? It sounds like distortion of a seal due to the vacuum.?

Any other thoughts?

Bob

My switch wasn't hissing as loud as I would expect. The local expert/dealer suggested replacement based on my (similar) symptoms, and nailed it.

I'm struggling with your observation of the lack of leakdown when turned off as nothing is "energized" unless the system is pumping. Could it be that it is turned off when you are away from the boat, with other systems that might contribute to an intermittent leak, say through vibration, or boat movement are also turned off?

 

[bobk]

Egaito, Sorry, I didn't explain it very well. If we turn off the toilet system/vac pump for a few days, it will leak all the way down. If I then turn it on and pump up the vacuum, it will hold a vacuum (not cycle) for at least 90 minutes. The the first time it is used, even water only, it begins to cycle every 15 minutes. Strange. Any other ideas?

Pascal, my vacuum switch has a wheel as you describe. And I turned it, but have no idea if it did anything.

Bob

 

[Gina Marie]

I been down that road I called Enviromental @18005222656. These guys were great a little anal but great!!!!


Tom Gina Marie

 

[Trojan]

I would recheck the duck bills. In use one may be distorting. When it sets for awhile it then has a chance to seal its self.

Bill

 

[bobk]

Thanks for the additional ideas. I hope it is as simple as distortion of the duckbills. I'll have a try at re-installing them tomorrow when the ER cools.

And I left a message with Environmental Marine Systems with a request for help.

Does anyone think the new pump diaphram could have developed a small leak in just a few months? And could a leak in it slow down after a period of non-use? Seems less likely than a duckbill issue.

I haven't tried to get my ear close to the vacuum switch on the reservoir... it's up against the ceiling in an akward place, but I have my grandson with me this week and maybe he can get to it for a listen. Could you hear any hissing? Maybe a stethescope would help.

Again, many thanks for the suggestions.

Bob

 

[yachtsmanbill]

You can use a straw or even the vacuum cleaner hose to listen. Youd be surprised how noise travels! ws

 

[bobk]

Environmental Marine Systems suggested I separate the toilet from the vacuum system, which I did by plugging the intake to the vac accumulator tank. No leaks for hours. OK, so next I reconnected the hose to the toilet... voila, the pump is cycling every 13 minutes. OK, so now I know where to look, but it's late, so I shut the thing down for the night. This morning, I energenized the system again and IT DIDN"T LEAK for hours. AHA, so I flushed it. Still no leak. I sat on it and wiggled it around, flushed a few more times, still NO LEAK. Doncha hate this kind of problem? You can't fix it if it gives no systems. But at least I think I have eliminated the four duckbills.

Ideas?

Bob

 

[Pascal]

i don't know which head you have but some VF have a soft gasket at the base. i had one of these on my previous boat, if overtightend, they will leak. you can hear the hissing though..

 

[egaito]

There is a kit to replace the ball, and the seal in the toilette, and the soft seal at the base. Best to go ahead and do both, and your problem will be gone for a good time to come.

 

[bobk]

There is a kit to replace the ball, and the seal in the toilette, and the soft seal at the base. Best to go ahead and do both, and your problem will be gone for a good time to come.

I thought you only changed this when it didn't hold water in the bowl. Mine does.??

Bob

 

[egaito]

I thought you only changed this when it didn't hold water in the bowl. Mine does.??

Bob

If you've isolated it to the bowl, and it does hold water, it's likely the lower seal. For my time and money, I would replace both at the same time as you'll have it apart.

 

[bobk]

Again, thanks for the advice. I got under the bowl and could hear the leak and using a long screw driver for listening, pinpointed it to the bowl seal. A new seal seems to have done the trick. Easy when you know where to look.

I also want to pass along a solution to a water leak that I didn't know I had. The vacuum break on the water supply had been leaking slowly and a PO stuffed the area with paper towels. A new vacuum break didn't fit... design has changed. But the leak was at the foam rubber compression sleeve (not available) but I was able to cut a piece of a soft dishwasher to disposal sleeve to fit and it seems to be tight.

Bob

 

[MikeP]

You know...I'm not understanding something. Everyone seems to say these Vfs t are great, there sure seem to be a lot of posts that indicate otherwise...