Vacuflush VG4 -- how often do you replace pump bellows too?

I had a ton of problems with my Vacuflush head last year. I wound up doing a "total" pump rebuild, which was duckbills plus a new bellows assembly and it worked like champ. Until I discovered the pump out hose was permeated (no pumpout occuring...) and overflowed the tank. I fixed that with a new pumpout hose (bitch of a job, tho) and felt like I was good.

Mid-season this year we began to lose vacuum again and I replaced just the duckbills. This solved the problem for a couple of weeks, but now we're back to zero whoosh at the toilet and a vacuum pump that seems to want to run continuously.

I was surprised when I pulled out the duckbills this year how crusty they were from urea crystallization after only a year. My guess is this is a function of low water consumption the Vacuflush system is basically designed for, and began flushing with a little added water in the hopes I'd dilute and rinse the path better.

Now I'm wondering if we don't have some kind of bellows problem again -- the one I pulled out last year was cracked and obviously contributing to the problem. Although since it was my first year with the boat, I don't know if those bellows were 2 or 10 years old.

In the back of my mind I'm also thinking I probably will ultimately need to replace the head->pump hose, since it probably has some permeation problems too. Although I tell myself if it was bad enough to totally ruin suction, duckbills or bellows replacement wouldn't have worked before. I hate the thought of this project, though as that hose routing looks like a truly awful job.

I figure I'll spring for another rebuild kit with new bellows, too, and see if it returns the system to normal. If not, then maybe it's time to grit my teeth and tackle the other hose.

Does the toilet "hold water"? Meaning, does the level stay between flushes or does it go down? If the water won't stay in the bowl, the seal around the ball valve is either dirty or needs changing.

Additionally, I tell my family and guests, when they flush, to hold the pedal down to the count of 3, but when they get to 2, to start over. I figure more water is better than less water. Also, I am a #1 boat only.

If the bellows are cracked again, I would suspect that you are not building any vacuum, but that doesn't seem to be your symptom. Does the vacuum generator run excessively? I am not sure if this is a true metric, but I have read a bunch and watched numerous YouTube videos on this topic and it seems that 60-70 "cycles" of the vacuum generator is about right. You know, the Ka-clunk, ka-clunk, etc.....

Good luck.

Jaybeaux

mobocracy said:

I had a ton of problems with my Vacuflush head last year. I wound up doing a "total" pump rebuild, which was duckbills plus a new bellows assembly and it worked like champ. Until I discovered the pump out hose was permeated (no pumpout occuring...) and overflowed the tank. I fixed that with a new pumpout hose (bitch of a job, tho) and felt like I was good.

Mid-season this year we began to lose vacuum again and I replaced just the duckbills. This solved the problem for a couple of weeks, but now we're back to zero whoosh at the toilet and a vacuum pump that seems to want to run continuously.

I was surprised when I pulled out the duckbills this year how crusty they were from urea crystallization after only a year. My guess is this is a function of low water consumption the Vacuflush system is basically designed for, and began flushing with a little added water in the hopes I'd dilute and rinse the path better.

Now I'm wondering if we don't have some kind of bellows problem again -- the one I pulled out last year was cracked and obviously contributing to the problem. Although since it was my first year with the boat, I don't know if those bellows were 2 or 10 years old.

In the back of my mind I'm also thinking I probably will ultimately need to replace the head->pump hose, since it probably has some permeation problems too. Although I tell myself if it was bad enough to totally ruin suction, duckbills or bellows replacement wouldn't have worked before. I hate the thought of this project, though as that hose routing looks like a truly awful job.

I figure I'll spring for another rebuild kit with new bellows, too, and see if it returns the system to normal. If not, then maybe it's time to grit my teeth and tackle the other hose.

Click to expand...

We have never had a bellows failure on our head. Current boat is 14 years old and all head parts are original and working properly. Our system does get a lot of use too. Previous boat was pretty much the same although we only owned that boat 7 years. I believe the key to keeping these systems working trouble free is to do a really good job of irrigating the tank at pump outs. We hold our pedal down for two minutes during a pump out while the tank is being pumped. We also add a cup of Tide laundry powder and flush that to help with tank cleanliness. When the boat goes into storage, the tank contents show clear water coming out. After cleaning the bowl before storage, I put a thin coat of Vaseline on the seal around the ball in the bowl to keep it from drying out over the winter. Using too little water during flushes casuses urea crystals and permeation oders to develop. Following directions when using. Have a talk with your teenagers about how things are to be used if they are on board.

I don’t get any vacuum at the head now matter how long I let the pump run. Before when it worked the cycle time was pretty consistent.

My bowl holds water fine so I think the bowl seal is still ok.

Replacing the pump bellows isn’t much more work than the duckbills so it’s worth doing simple to ensure that part is up to snuff.

If I still don’t generate any vacuum (and I know how to test the pump/accumulator alone) I’m going to assume that permeation won on the toilet hose and start seeing what replacing that looks like. The waste hose goes curves back behind the holding tank into a bilge chase and I think toilet access is from a hatch in the mid cabin just behind the bathroom. What I worry about are inaccessible brackets holding the waste hose down as pulling the old hose out will be a total bitch as will fishing a new one.

mobocracy said:

I don’t get any vacuum at the head now matter how long I let the pump run. Before when it worked the cycle time was pretty consistent.

My bowl holds water fine so I think the bowl seal is still ok.

Replacing the pump bellows isn’t much more work than the duckbills so it’s worth doing simple to ensure that part is up to snuff.

If I still don’t generate any vacuum (and I know how to test the pump/accumulator alone) I’m going to assume that permeation won on the toilet hose and start seeing what replacing that looks like. The waste hose goes curves back behind the holding tank into a bilge chase and I think toilet access is from a hatch in the mid cabin just behind the bathroom. What I worry about are inaccessible brackets holding the waste hose down as pulling the old hose out will be a total bitch as will fishing a new one.

Click to expand...

When you are ready to pull out the old hose, connect one end of the new hose to it and fish the new hose in and the old one out in a single operation.

bobeast said:

When you are ready to pull out the old hose, connect one end of the new hose to it and fish the new hose in and the old one out in a single operation.

Click to expand...

Yeah, I plan on something like that. I'm not sure it will help removal of the old hose, though. When I removed the old pumpout hose it was really stiff and awkward to work with and that was with very little "fishing" involved, mostly navigating the existing plumbing/wiring. Given the 180 turn in the engine room (astern of the holding tank), it's gonna be awkward to both pull out the stiff old hose and get new hose to feed.

I'm kind of tempted to just attach electrician's pull string when I pull out the old hose and then use it to feed in the new hose. The replacement will be Raritan Saniflex which is extremely flexible and easy to work with.

I have two VG4’s on my boat and just recently replaced duck bills for the second time in 5 years and just one of the bellows assemblies. I replaced the bellows as that unit (the master head) was not generating vacuum and I had liquid waste on top of the bellows. The parts counter guy told me to expect 5 years out of duck bills and 10 out of the bellows. Right on time. Not a hard job but definitely disgusting. To the OP, I assume you know there are two sets of duckbills that need to be replaced on your VG4...

Before you start doing any repairs, remove the hose going to the toilet... plug it... see if the pump builds pressure and turns off. This will narrow down your search area. You can buy a vacuum gauge/tool for this purpose or just do plug it any old way you want to. You can "plug" in various ways to test the different section.

A quick and easy thing, that "might" help you get lucky, is to get down next to the tank and let it run for a minute. Then have someone turn it off and immediately listen for air leaks. It could be one of the seals on the tank. It's worthwhile to do that before anything more major.

Lazy Daze said:

Before you start doing any repairs, remove the hose going to the toilet... plug it... see if the pump builds pressure and turns off. This will narrow down your search area. You can buy a vacuum gauge/tool for this purpose or just do plug it any old way you want to. You can "plug" in various ways to test the different section.

A quick and easy thing, that "might" help you get lucky, is to get down next to the tank and let it run for a minute. Then have someone turn it off and immediately listen for air leaks. It could be one of the seals on the tank. It's worthwhile to do that before anything more major.

Click to expand...

And - the electrical vacuum switches do fail; they have a rubber diaphragm that will eventually crack and leak air. The switches are a "self-eating watermelon" as when they fail they cycle more and more and then get worse and worse because they cycle more and more.

Lazy Daze said:

Before you start doing any repairs, remove the hose going to the toilet... plug it... see if the pump builds pressure and turns off. This will narrow down your search area. You can buy a vacuum gauge/tool for this purpose or just do plug it any old way you want to. You can "plug" in various ways to test the different section.

A quick and easy thing, that "might" help you get lucky, is to get down next to the tank and let it run for a minute. Then have someone turn it off and immediately listen for air leaks. It could be one of the seals on the tank. It's worthwhile to do that before anything more major.

Click to expand...

That's a great suggestion although I'm worried that removing the hose at the toilet will be impossible to do in a non-destructive fashion. When I replaced the pump out hose (same hose material as far as I can tell) it was a real bear to get it off the two fittings it was attached to. No amount of mechanical force I could apply would budge the hose, I literally had to cut it away to get it off.

I am about to break down and buy a vacuum gauge, too, just so I can more sanely test various parts of the system. I wish they had a stopper of some kind you could drop into the bowl to test vacuum end-end.

Remove the hose GOING to the toilet. Meaning, remove the hose at the vacuum tank and plug there at the tank. If that builds and holds pressure, you know the issue is upstream. If it doesn't hold pressure, you know the issue is there at the tank. It'll at least get you narrowed down.

Yeah, those hoses can be a real bear to work with. There are obvious precautions that have to be taken with this, but heating up the hose with a heat gun can help.

Lazy Daze said:

Remove the hose GOING to the toilet. Meaning, remove the hose at the vacuum tank and plug there at the tank. If that builds and holds pressure, you know the issue is upstream. If it doesn't hold pressure, you know the issue is there at the tank. It'll at least get you narrowed down.

Yeah, those hoses can be a real bear to work with. There are obvious precautions that have to be taken with this, but heating up the hose with a heat gun can help.

Click to expand...

Yeah, I've yanked the sewage "supply" hose to the vacuum accumulator before to manually check the vacuum pull. IIRC, it wasn't super strong even after replacing the duck bills this summer. Of course my impression isn't an objective measurement so it may have been fine which is why a vacuum gauge is now appealing as it gives me a real number.

ttmott said:

And - the electrical vacuum switches do fail; they have a rubber diaphragm that will eventually crack and leak air. The switches are a "self-eating watermelon" as when they fail they cycle more and more and then get worse and worse because they cycle more and more.

Click to expand...

Supposedly the failing vacuum switch is a problem if you have good vacuum but excess pump run time. Not sure if it can cause problems generating sufficient vacuum due to leaks, which is more my problem.

mobocracy said:

Yeah, I've yanked the sewage "supply" hose to the vacuum accumulator before to manually check the vacuum pull. IIRC, it wasn't super strong even after replacing the duck bills this summer. Of course my impression isn't an objective measurement so it may have been fine which is why a vacuum gauge is now appealing as it gives me a real number.



Supposedly the failing vacuum switch is a problem if you have good vacuum but excess pump run time. Not sure if it can cause problems generating sufficient vacuum due to leaks, which is more my problem.

Click to expand...

I had a similar problem as your system's leak-down and high pump cycling. It ended up being a small tear in the switch diaphragm. The switch still functioned normally but it was the source of the air leak.

ttmott said:

I had a similar problem as your system's leak-down and high pump cycling. It ended up being a small tear in the switch diaphragm. The switch still functioned normally but it was the source of the air leak.

Click to expand...

Enough air leak to not flush the system from the head, or just high pump cycling?

mobocracy said:

Enough air leak to not flush the system from the head, or just high pump cycling?

Click to expand...

High pump cycling. I suppose if the tear in a switch diaphragm was big enough then the switch would not actuate off and the pump would run continuously and a vacuum would not develop due to the size of the tear. Seems if not enough vacuum to be able to flush the head the pump would run continuously. Switch is easy to check; four screws and you can visually inspect the rubber diaphragm on the underside.

ttmott said:

High pump cycling. I suppose if the tear in a switch diaphragm was big enough then the switch would not actuate off and the pump would run continuously and a vacuum would not develop due to the size of the tear. Seems if not enough vacuum to be able to flush the head the pump would run continuously. Switch is easy to check; four screws and you can visually inspect the rubber diaphragm on the underside.

Click to expand...

Thanks. I'll be checking that this weekend when I dive in and see if I can fix it again.

Well it’s “fixed”, but I’ll be damned if I can figure out why short of poor reassembly when I swapped duckbills last time.

I started out by turning the system on and letting it run. I think it’s always cycled a little when first powering on but I let it run for a few minutes and checked the head for any sign of vacuum. No audible vacuum but with the valve open and some water dumped in the water way down at the base fitting would mostly disappear. I also tried a very poor mans vacuum gauge by holding a trash bag in the toilet with the pump running and the flush ball valve open and I did some some signs of vacuum consistent with the small amount of water disappearing.

I next disconnected the septic hose from the vacuum tank and checking for a vacuum. It seemed ok but kind of weak and the accumulator was full of liquid. I taped off the accumulator input really well and plugged the pump back in and it ran continually which seemed to suggest a leak somewhere in the pump and outlet assembly, as I would have expected it to quickly draw a good vacuum and shut down.

I disassembled as per a duckbill replacement to look for obstructions or bad gaskets (the one at the pump base especially) and found nothing. I double checked everything per my exploded diagram and it was all correct with no missing parts or bad orientation.

I put it all back together and made extra sure all the pump outlet tail pieces were tight. I was feeling pretty dejected with no obvious signs of a problem. I plugged the pump back in and let it run and it seemed to sound different. I pulled the tape on the inlet fitting and sure enough, a pretty good sucking sound. I put the septic hose elbow back on and fired it back up. The pump was running but by the time I got to the head a really good whooosh. Filled the head with water and whoosh, it got sucked down good. I waited and less than a minute the pump shut off as per normal.

It seems “fixed” but I use quotes because there’s still some kind of leak somewhere as the pump cycles for about 5-15 seconds every 5 or so minutes. No noticeable loss of bowl water and normal flushing has normal levels of pump cycle time.

All I can think is that I didn’t put to back together snug enough when I replaced duck bills.

I manage to lose my 7/16” socket in all this.

Well, that sounds 99% positive! For the remaining 1%... where do you think the socket is? Possibly in the pump/duckbills preventing the duckbills from sealing completely?

Lazy Daze said:

Well, that sounds 99% positive! For the remaining 1%... where do you think the socket is? Possibly in the pump/duckbills preventing the duckbills from sealing completely?

Click to expand...

Haha. No the socket fell between the vacuum accumulator and the septic tank, it’s gone unless I make a big effort to find it.

My guess is that the seal between the pump housing and the vacuum tank is poor or the tail piece fittings between pump and main septic tank leak just enough to bleed off vacuum. My vacuum switch may be at the end of its life, too.

When I do this again I’m thinking of using an overall larger gasket on the pump housing base.

I also don’t quite understand why there are so many PVC pipe segments between pump and tank. I guess there’s some need to hold duck bills in place but it’s an awkward number of segments in a short space and it complicates re-mounting the entire assembly and getting snug tightness.

I also can’t deny that boat plumbing is everything I hate about home plumbing in a smaller space. That might color my analysis and task performance.

Mo - I use a light coat of silicone grease on reassembly of the gaskets and PVC segment threads.