Vacuum leak on VacuFlush on 2001 3988

[Ahaua]

Ok, I've already replaced the duckbill valves on the vacuum generator and, based on a good tip, used shaving cream to try to find a continued vacuum leak on the the vacuum generator; it all checks out ok. I'm now focusing on the VacuFlush toilet. Before taking everything apart, I used the shaving cream trick on the vacuum lines and no luck. I can hear a faint noise coming from the inside of the toilet so my next step is to take it apart and look inside. I'm going to order a ball valve seal kit before I do this so that I can take advantage of having everything apart and replacing the seals. Anyone have any words of wisdom?? Btw, the toilet bowl is holding water just fine, but the vacuum generator turns on way too frequently....somewhere, vacuum is leaking...

[brad4550]

Hi Alex

If it's holding water...and your hearing an air leak your on tha right path...make sure you also replace (not sure what comes in kit) "O"rings on half ball shaft also toilet to base gasket,might as well replace ball gaskets also if not in kit pay attention to

"This Side Up"and which one goes on base first ... Good luck Brad

*note a vacuum gauge works great for isolating problems .

[Ahaua]

Thanks Brad. I'm gonna order a kit and get to it; it'll be my first time taking the toilet apart so, thank God for Youtube....lol. I'll report back with my findings and hopefully a fix.

[Jeffw]

I had a Vacu-flush on my 2007 305 that cycled a lot. I could never isolate the problem, so I changed the toilet power lead to the water pump switch. Water pump/toilet on to flush, then off. Worked well, but didn't really fix the problem.

[higgins_jr]

Ahaua, assuming you've changed the ball seal, (2 part rubber discs that hold the water in the bowl) there are a couple of other places to investigate. There is an O ring where the foot pedal mechanism goes thru the neck stand to the ball. I've had a leak there. Also there is a funnel under the ball that connects to the vacuum hose to the generator. It's visible when you hold your foot on the pedal and open the ball to flush. A decade or so back, according to our local importer, there was a bad batch of funnels that had minute hairline cracks in the base which deteriorated over time. That was allowing the vacuum to leak which in turn was starting the vacuum generator every 15 mins or so. Water was staying in the bowl as the seals were doing their job.

To get to the funnel, remove the bowl, and undo the (4?) screws/bolts holding the neck base to the floor. Provided there is a little slack hose, you should be able to get the funnel out and off the hose for inspection. I had a few minute cracks on the underside, so I replaced the funnel and solve the problem - they aren't that expensive, but you should replace the foam base seal while you're at it.

A vacuum gauge from the mfgr will tell you if you're loosing vacuum, but that may be obvious. If it's not the funnel or the pedal o ring seal, then check the hose clips both ends. You can even jam a plug in the end of the disconnected hose (funnel end) and start the pump to isolate the hose and see if it holds vacuum over time. It's a process of elimination back to the pump or from the pump forward. Have fun! Cheers

[Ahaua]

John,

this is very valuable information; thank you! It sounds like this may be a possible source for the leak since it does appear that the seals are doing their job. Gonna order parts and I'll do as you instructed.

Thanks again!

[cptncptn]

+1 on the funnel. I had a small vacuum leak, the pump would run every 45 mins. Changed every thing, no change. Ended up being the funnel, it had a small crack. Now holds vacuum for 6 hours.

[Ahaua]

I've already ordered and received a few parts in hopes that it results in success, (seals, new ball, cartridge....). What is the official name of the "funnel"?.....If it's not included in the parts I ordered, I will most likely order it before I take everything apart. Btw, I have a Vacuflush model 147.

[higgins_jr]

Alex, it may well be that the model that I'm familiar with is different than yours. I've included a URL with a schematic I found that shows the funnel component at the bottom. It sits at the bottom under the unit, possibly equivalent to what's labeled on yours as the "discharge kit". https://www.environmentalmarine.com/...506-parts.html

The best "shitter store" I know is next to Fisheries Supply in Seattle. https://www.marinesan.com/AboutUs.asp

I'd call them and see if my observations have relevance with your particular model which is different from mine. But I'd guess it's the discharge kit that you're after. They will have the part, but check out the pricing.

Have fun. Cheers

[Ahaua]

John,

Thank you! This information clears things up a bit. I'll contact them and inquire about this part since it may, very well be, the culprit.

Alex

[businessgetmoney]

So side note, what do you have to winterize with a vac flush? Im a bit worried ive never had one. I flushed down a bunch of antifreeze but im not sure.

[Ahaua]

Update on fixing a vacuum leak on a VacuFlush, (model 147). As I stated before, I started off by installing new duckbill valves on the vacuum generator; however, this did not fix the problem. I then used shaving cream on parts of the vacuum generator in an attempt to detect any leaks; none were found. My focus then went to the toilet. The shaving cream trick didn't reveal any obvious leaks but I could hear a very faint leak inside the toilet. keep in mind that the toilet was holding water just fine. After some research, including this forum, I ordered a new bowl seal kit and a new Flush Ball and Shaft Kit. This includes the ball, cartridge, brass rotor shaft, (original rotor shaft was plastic), and screws. The rotor shaft has two rubber O rings, and I believe that this was the source of the vacuum leak. After replacing the above, no more vacuum leak!