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

carterchapman said:

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

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That might do the trick on the PVC segments, thanks. I still think a better gasket on the pump base / vacuum accumulator tank isn't a bad idea.

Mo - You can get a small tube of silicone grease at the Home "Despot" in their plumbing section...

I've just replaced the 4 duckbills in one of mine - found a panty liner stuck in one of them - thank you ladies! I'm showing 10" of vacuum at the toilet base, but now my pump won't shut off... so I'm going to replace bellows today - there are two gaskets that go with the bellows replacement...I'll let you know how it goes...

My aft head shows 10.2" of vacuum at the toilet base...and it shuts off fine...

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.

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My pump runs every 5 minutes or so... The bowl holds water for weeks. I have replaced duck bills and checked #9 and #10 pieces on the diagram for proper seating. Also have listened for leaks.

Lazy Daze - These are a couple good tips i will try next. I also ordered a new Pressure switch.

Attached...Ran across this troubleshooting guide from Dometic... Might be helpful to some folks...

rlynch03 said:

My pump runs every 5 minutes or so... The bowl holds water for weeks. I have replaced duck bills and checked #9 and #10 pieces on the diagram for proper seating. Also have listened for leaks.

Lazy Daze - These are a couple good tips i will try next. I also ordered a new Pressure switch.

Attached...Ran across this troubleshooting guide from Dometic... Might be helpful to some folks...

Click to expand...

To clarify, I meant remove the "head hose" where it attaches in the bilge. This will eliminate that hose and everything further upstream as a variable. It will allow you to focus attention in the bilge. If all of sudden things work perfectly, then you also know the issue isn't in the bilge.

rlynch03 said:

My pump runs every 5 minutes or so... The bowl holds water for weeks. I have replaced duck bills and checked #9 and #10 pieces on the diagram for proper seating. Also have listened for leaks.

Lazy Daze - These are a couple good tips i will try next. I also ordered a new Pressure switch.

Attached...Ran across this troubleshooting guide from Dometic... Might be helpful to some folks...

Click to expand...

I had the "pump runs frequently" problem last season and wound up doing another complete internals replacement *and* a pressure switch. My problem wasn't lack of function -- it flushed fine, it was excessive pump cycling and not shutting off even though it was pulling 12" of mercury on a vacuum gauge at the head.

I started out with the assumption that the duckbills were OK if it would draw that good of a vacuum, so I replaced the vacuum cutoff switch first. But that didn't help, so I just did the rest of the vacuum pump rubber. That didn't solve it either, and since I had a bellows, I did that and it solved the problem, after which I noticed bellows I replaced had a hairline crack in them.

The runaway vacuum pump problem also pissed me off enough to do something about it -- I put in a timer relay circuit in front of the pump motor. Each time the motor is activated by the pressure switch, it can only run for 4 minutes until the head system power is shut off, which resets the timer relay. This way if there's some minor loss of system vacuum but the toilet still works, you don't sit at anchor for an hour or two while your vacuum pump motor runs non stop draining the battery. I think this is a feature the head system should have come with in the head control panel, along with some kind of status light indicating it kicked in.

The Vacufluh concept I guess is OK, but the execution needs some of the problem areas dealt with. Like a different vacuum generation setup -- use a normal check valve between accumulator and the holding tank and let it gravity feed the holding tank, so the vacuum pump doesn't actually need to pump raw sewage. It would also help if the septic line between head and vacuum accumulator used solid PVC pipe.

IMHO, the Vacuflush system works well when it works but that its kind of funky and prone to problems. If ever have the chance to order a brand new boat with a head, I want an electric macerating toilet instead.

I know there are lot of moving parts, but my approach is keep it simple and cheap as possible first... With two heads, the aft being as trouble free as you could ask for and the master being problematic, but both being on the same maintenance schedule... I started using Noflex Digester and the cycling of the pump is gone.

My aft head vacuum generator (VG4) will create a vacuum and flush, but the pump will not shut off. I am running out of parts to replace, having replaced the duck bills, bellows and gaskets. I'm thinking of checking the pressure switch and would like to know how to do so and how many parts on that device can be replaced? Is it only a diaphragm and the switch itself?

Captsteve427 said:

My aft head vacuum generator (VG4) will create a vacuum and flush, but the pump will not shut off. I am running out of parts to replace, having replaced the duck bills, bellows and gaskets. I'm thinking of checking the pressure switch and would like to know how to do so and how many parts on that device can be replaced? Is it only a diaphragm and the switch itself?

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There's some suggestions, above, to "test" various areas - in other words: diagnose first, don't just replace. Give those suggestions a try.

The switch might just have a worn o-ring - or, the switches do get "tired". But again, read through the suggestions - including listening closely for the hiss.

Captsteve427 said:

My aft head vacuum generator (VG4) will create a vacuum and flush, but the pump will not shut off. I am running out of parts to replace, having replaced the duck bills, bellows and gaskets. I'm thinking of checking the pressure switch and would like to know how to do so and how many parts on that device can be replaced? Is it only a diaphragm and the switch itself?

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The switch is a one-piece unit with no real replaceable parts. I think if you were stuck in the apocalypse you could MacGyver some kind of repair, but if your time means anything its just a complete replacement.

It's also a crap mechanical switch which uses diaphragm pressure to pull a spring under vacuum to disengage the switch and is vulnerable to corrosion which can affect its ability to cut in or out. I'd have a bit more respect for it if the spring and switch were environmentally sealed, as well as if it was intended to be adjusted (I think you might be able to adjust it, but I don't think it was designed for easy adjustment).

In my opinion, its another part of the Vacuflush system that needs re-thinking.