Vacuflush waste tank air leak

[jbarneymi]

Hello everyone. New to this group and looking forward to contributing where I can. I have a boat that has a Vacuflush system with a 10 gallon holding tank. I'm not familiar with this holding tank setup and can't find much online specific to this tank (2001 era). I'm trying to figure out how this setup works as there appears to be 3 different chambers/tanks. I have an air leak as the system will only hold pressure for about 1 minute. I was able to spray all external connections with soapy water and fixed 3 leaks but there is still one somewhere else. Any suggestions? I also check the toilet seal and that is not leaking. Are there duckbill valves somewhere that maybe need to be replaced? Thanks in advance!

[Fuss]

There are duck bill valves in the inlet and outlet hose fittings on the pump…pull these off and look…also pull the pump apart and check the concertina type pressure unit inside the pump. I have a tube shaped tank so I’m not familiar with this rather complicated looking vacuum tank.
There is a contact breaker that switches off the pump under the conical looking cover…if the pump does in future not switch off then this might need maintenance too.

[AnsleyS]

Fuss is correct but I would suggest that you get the service info and get a duck bill kit before you open it up. The most common places for leaks are the head seals, the seal around the head flush pedal, the duck bills at suction pump and the seal around the vacuum pump switch. Pay attention to reverse threaded connection at the pump.



Use foam shaving cream rather than soap water because the suction is more visible with the foam.

[peghall]

None of those tanks are holding tanks, they're all part of a "vacuum generator," and I THINK the one you have is a Dometic/SeaLand "Low Profile Vacuum Generator VG3." Or possibly a VG4.

https://www.environmentalmarine.com/...eatured&page=2

That link just happens to be to the dealer where I found the exploded drawing and parts list that should tell you what all the parts are and what they do and how the system works. You should be able to get an owners manual from them if nothing else....I think you need one!

--Peggie

[jbarneymi]

Thank you everyone, this is SO helpful and really helps point me in the right direction! I sure appreciate it!

[jbarneymi]

Originally Posted by AnsleyS

Fuss is correct but I would suggest that you get the service info and get a duck bill kit before you open it up. The most common places for leaks are the head seals, the seal around the head flush pedal, the duck bills at suction pump and the seal around the vacuum pump switch. Pay attention to reverse threaded connection at the pump.



Use foam shaving cream rather than soap water because the suction is more visible with the foam.

The notes you made on the picture is super helpful! Thank you!

[knot smart]

Good afternoon

please refer to the link

https://www.environmentalmarine.com/...ow-profile.pdf

i had to completely rebuild two systems last summer.. part number 12 (the rubber grommet) is most likely why youre losing pressure.. i read online those go just as often as the duck bills.. before i leave the boat i always make a point to step on the flush pedal to let all the pressure out while not on the boat.. i also had a cracked #7.. i replaced all the grommets, switches and pumps .. theyre cheap.. amazon.. i have to say, after i rebuilt the system , i love it.. sure beats the old hand pump system we had on the last boat.. that thing flushes like port authority

[jbarneymi]

Good morning all! I'm still trying to figure this out but here is where I'm at: I replaced all the seals on the vacuum tank as well as all 4 duckbill valves and the two o-rings going into the vacuum tank (item 11 in the diagram). My vacuum pump won't shut off at all and I'm only getting a max reading of 7 Hg on the vacuum gauge (when inserted into the toilet). If I go and manually shut off the pump, the system stays charged at 7. In my research it appears it should be in the 10-12 range, is that correct? So, does this sound like a pressure switch problem or a pump problem?

[peghall]

Sounds like you need a new vacuum tank switch (which I think is what you're calling the "pressure" switch. That switch is NOT adjustable...messing with it will screw it up. MarineSan in Seattle will have it for the best price.


--Peggie