Vacuflush - vacuum leak

Debt-icated

Debt-icated

Member
Apr 11, 2007
115
Spokane, WA
Boat Info
'10 310 Sundancer
Tow Vehicle: '21 F-250 Powerstroke
Engines
Twin 5.0L DTS
Bravo III
Struggling here... I have had issues with my Vacuflush system basically for 7 months now. Last weekend my vacuum pump would continuously run and the toilet had no vacuum to flush. I have had issues with the pressure switch before so I fiddled with that but had no luck getting the pump to stop running. I ordered a new pressure switch and installed today. Now am able to create enough vacuum to flush water down the toilet, but the pump still will not shut off. I have run probably 10 gallons of water through the system so I am fairly confident the lines are not clogged. Before I gave up for the night, I went into the bilge and placed my ear close to the vacuum pump.. When the pump is trying to generate vacuum I can hear an air leak at the base of the pump. If I hold down the pressure switch to shut off the pump the air leak slowly fades away. Anyone experienced this? Any ideas?
 
That pump operates a plastic diaphragm and there are some O-ring seals which are maintenance items. Sounds like there is a crack or leak amongst the diaphragm or seals. Adjacent to the pumping mechanism are the rubber "duckbill" check valves; there are four of them and they are a maintenance item also.
The pump is easy to remove, disassemble and retrofit with new softgoods; access to it withstanding.
If you are going to work on it might as well do a complete rebuild - http://seacoastservices.com/vacuflush-maintenance-kits/
 
I agree with ttmott. I've had the same issues with mine before. Replaced the four duckbills, then found that the bellows which is the plastic accordion type diaphragm in the vacuum generator had actually cracked and split. Replaced that and my constant pump running stopped, and then ran about every 30 minutes. I then used an ultrasonic leak detector and located my final leak coming from the floor flange seal below the toilet. Replaced that and all good. Generally the factory setting on the pressure switch I've been told by many people should not be messed with. I would open up the vacuum generator, check the bellows, the o-rings and duckbills, replace as needed. It's a pain in the ass system, but a fairly simple one. I'm actually getting ready to change to a fully electric toilet and dump the entire vacuflush system.
 
I have all my parts in route right now to rebuild mine. It has the same issues you are experiencing. Order the kit from the link above and you should be fine.
 
I just finished replacing my master head last night. After a series of issues, I finally had it back together, no fresh water leaks, etc but it kept cycling and with that, I knew I had a vacuum leak somewhere. I turned all of my noise makers off to get the boat as quiet as possible. I had floor hatch open where the vacuum pump is located and sure enough with my head stuck in the floor I heard the vacuum leak. I grabbed a few of the lines and wiggled them until I found the culprit. I turned to be a PVC 90-degree elbow with 2 o-rings that were 18 years old and a bit flat. $5 later O'Reilly's auto parts I had my parts and no leaks......
 
thank you all for the comments. I just ordered the entire rebuild kit. I had it orvernighted as I have a long 4th of July weekend planned. I am hopeful I can actually fix this while on the water. That being said. I feel like taking the vacuum assembly off the tank should be easy. its just the 4 machine screws and unscrewing the outlet fittings that go into the tank? is that correct? It seems replacing all these seals would be a lot easier if i could work on it outside of the bilge. i have looked for videos on taking the assembly off, but have not found anything...
 
interested to know how you made out.
 
Replaced with entire re-build kit.still have vacuum leak. I am now leaning towards a possible crack in a plastic piece. Boat is going to my sea Ray dealer today, I'm tired of messing with it. Will post the outcome as soon as I get answers
 
After chasing a leak since last season, I found mine to be the sealing grommet for the pipe/elbow that goes into the vacuum tank.
 
I just rebuilt my vacuum pump with ne bellows and 4 duckbill valves. Works like a charm. Also soaked all the pump parts in acid for 1 hr. It cleaned them right up.
 
Having same issue on our 2005 320. I want to try replacing the O rings and the duck bill valves. How do I know which kit to get? I can't tell which series I have.
 
Another area to look at is the flush pedal mechanism on the toilet itself...a boater at our marina was chasing down a vacuum leak and found it there.
 
Ours was the elbow on the vacuum tank. It is a weak link on the design. Easy to bump when working in the bilge.
 
Do you recall what series vacuflush you have in your 320?
skolbe said:
Ours was the elbow on the vacuum tank. It is a weak link on the design. Easy to bump when working in the bilge.
Click to expand...
 
Haven't heard back from the OP on his progress so rather than start a new thread I'll continue many questions here. So I replaced the duckbill valves and the bellow along with the necessary o- rings in the bilge and no luck. Followed a suggestion and turned everything off and listened for leaks. I found a hiss coming from the area near the base of the bowl however I'm not sure how to proceed. The bowl will hold water for days with zero leaks so don't think it's the seal that sits directly on the clam shell valve. Any ideas? Are there other seals in this area that would cause a leak but not affect the water?
 
Like jthatcher says, the seal at the base of the toilet. I had a leak there as well. It's called a floor flange seal. Easy to change once you lift up the toilet.
 
Going to order and give it a try.
 
I may be doing this repair during some down time at the flotilla!
 
Just ordered my seals. Hope this does the trick. Ron did you order your parts?
rcmafgny said:
I may be doing this repair during some down time at the flotilla!
Click to expand...
 
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