Troubleshooting Vacuflush

[SV Demeter]

Vacuflush head seems to have developed a vacuum leak. It's a very slow one such that the pump will kick on briefly a few times over the course of the night or if I turn it off it won't have a vacuum come morning. Wondering how to check for leaks as I dont see anything leaking out of any hose junctions and have tried cleaning the bowl. Guessing vacuum is only between the head itself and that big cylinder thing and that between the cylinder and the holding tank where there is a macerator type pump is not under vacuum?

[Chief Engineer]

Vacuflush has a tool for checking vacuum.

I carry one in my truck.

Tells me where the leak is.

Usually Bowl seal...(These are suspect if owners are overweight.)

Fill the bowl with water...if it goes down overnight....it is the bowl seal

The other suspect is the vacuum switch on the accumulator tank.

And of course hoses.on the vacuum side....

[Bash]

Originally Posted by Chief Engineer

Vacuflush has a tool for checking vacuum.

I carry one in my truck.

Not many people can brag about that one, Chief.

[Hud3]

VacuFlush sells a kit for testing vacuum and replacing seals/valves. If it's the bowl seal, which as Chief suggests is the first thing you should check, you might be able to quick-fix it by simply burnishing the bottom rim of the bowl with the little stick that comes with the unit. It looks like a fingernail file, and it knocks of miniscule mineral deposits that cause that slow leak.

[SV Demeter]

Thanks guys. I was thinking bowl seal. I tried a little just cleaning the seal but because we have 2 heads this has not been a huge priority for me. Im going to I guess troll the internet for said Vacuflush tool kit and work the seal a bit more.

[SV Demeter]

So this looks like the tool:

DOMETIC CORPORATION 318530002 - Dometic Corporation VACUUM TESTER GAUGE 318530002 - Boaters Plus

but I already have a vacuum gauge in my tool kit. Do i need to spend $60 for one with what ever that thing on the end is? Also not seeing anything with the file that Chief refers to. Will head to boat this eve and see about water level dropping. I know the bowl seems to be keeping water in it but maybe its going down some? How can I test the switch? Still trolling the dometic site for info. Really hoping to not have to disconnect any of the 1 1/2" odorsafe hoses...

[peghall]

If it's been at least two years since the duckbills in the vacuum were replaced, it's a good bet that's where the air leak is...replacing 'em will solve the problem.

But first, I'd try flushing at least two FULL bowls of water through it. I may be that there's just some waste or TP stuck in one of the duckbills that's keeping it open. That happens a lot to owners who believe that V/Flush doesn't need more than a pint of water/flush.

If the bowl holds water, it can't be the bowl seal or the dome in to the bottom of the bowl.

And while a vacuum tester gauge is dandy tool, it's a PITA to use to find an air leak in a V/Flush system. There's a MUCH easier way to hunt down an air leak: Squirt a LITTLE shaving cream onto each hose connection...flush the toilet. The suction will pull the shaving cream into any connection that's leaking...it'll just sit there on all the ones that aren't.

From your description of the vacuum tank as "big cylinder thing," I suspect you don't have an owners manual for it. You need one...'cuz it includes a trouble shooting guide that covers just about every possible symptom that a V/Flush toilet can develop, the possible causes and cures. You can download and print one from the Dometic SeaLand site here: VacFlush Owners Manual And it doesn't matter how old yours is, 'cuz the VacuFlush hasn't changed enough to notice, except cosmetically, since it was first introduced by Mansfield in the 1970s...so the current manual's trouble shooting guide is just as good for a 20 year old V/Flush as it is for a brand new one.

Or...I see you're in Annapolis...the sailboat show starts on Thursday. Invest in a ticket and spend some time in the SeaLand Dometic booth learning how a VacuFlush works (there is no macerator in it) You can pick up an owners manual there too.

Meanwhile, this may help:

VacuFlush 101, Part 1--How it Works:

It's a 3 component system--the bowl assembly, the vacuum accumulator tank (not to be confused with a holding tank) and a vacuum pump. The vacuum tank and vacuum pump may be a combined gizmo called the "vacuum generator," but it includes both and works the same way as separate vacuum tank and pump. The holding tank is NOT part of the VacuFlush toilet system, and neither is the tank overboard discharge pump...SeaLand just bundles holding tanks and discharge pumps with the toilet system.

The vacuum pump has TWO functions: it suctions the air out of the plumbing between the toilet bowl and itself while simultaneously pushing the flush the rest of the way to the tank, treatment device or thru-hull. The vacuum tank has a switch and a sensor on it that starts the vacuum pump when there's a loss of "vacuum" (toilet is flushed or an air leak in the system) and turns it off when the correct amount of negative pressure has been reached. How long it runs depends on the distance from the pump to the bowl...the shorter the distance, the shorter pump run time. The accumulated "vacuum" only pulls the bowl contents TO the pump..the pump has to push it the rest of the way.

Air leaks are the only thing that will cause the vacuum pump to cycle between flushes for no reason. The most common source of air leaks is worn out duckbill valves or something (waste or toilet paper) caught em, in the vacuum pump 4 of 'em--2 in, 2 out...so if it does start cycling for no reason, first thing to do is flush a full bowl of water, even two bowls full. If that doesn’t cure the problem, replace 'em. They should be replaced about every two years as preventive maintenance anyway...even annually if you live aboard.

As duckbills become more worn, the pump will cycle more often and will run longer and longer each time. A failing vacuum tank switch can also cause the pump to run longer--till eventually it won't turn off at all unless you turn it off at the breaker--but that will NOT cause the pump to cycle for no reason.

VacuFlush 101, Part 2 Actual Flush Water Requirement

The two most common mistakes that V/Flush owners make are:

1) Easing the pedal back up instead of just letting it go.
It's spring loaded for a reason--to snap the dome back into place it with enough force to seat it and seal it. So just let it go! If you don’t, over time you’ll develop an air leak in the bowl.

2. Using too little flush water.
SeaLand's claim that the V/Flush can use "as little as" 1 pint of flush water is VERY carefully worded. If only urine is flushed...no water added to the bowl first, no TP either...then yes, you CAN get away with that little, at least for a few flushes. But if you do much of that, unless you want odor, at least once a day you need to run at least half a bowl of clean water through it to rinse out the system. It's also advisable to add at least half a bowl of water ahead of solids or any TP (iow, every time a female uses the toilet)...that's a quart or more. It's also essential to leave the pedal down for at least 7-10 seconds after the bowl is empty to rinse out the pump and duckbills--to prevent a buildup in the pump or bits of waste or TP from becoming stuck in a duckbill, creating one of those pesky air leaks that causes the pump to cycle for no reason...at least another quart. And if you don't want permeated hoses, it's a very good idea--last thing before the boat will sit (or at least once a week if you're living aboard)--to fill the bowl to the rim with clean water and flush it through to thoroughly rinse out the vacuum tank, hoses and pump...'cuz suction splatters waste all over 'em and the flush water flow isn't sufficient to completely fill the hoses. So, averaged out over a week, the VacuFlush actually NEEDS about the same amount of flush water as most other toilets that use pressurized flush water: about .5 gal/flush. If you're using much less than that, you're asking for problems.

Btw...I had V/Flush toilets on my last two boats and was also a dealer for nearly 10 years...so I'm INTIMATELY acquainted with 'em...what keeps 'em working trouble-free and what doesn't.

[SV Demeter]

Thanks Peg! I knew it was only a matter of time before you came to my rescue again... I am relatively new to the vacuflush system as it came with the boat. I have been using a lot more water as you suggest mainly on the forward head which has a long hose run back to the holding tank. I have had the boat for about a year and a half and suspect the vacuflush system is at least 5 years old. However the boat has not been used very much over that time and the head system sat winterrized for 2-3 of those years. The forward head gets very little use and is the one acting up. I suspect the duckbills have never been serviced. Im going to take your advice and download the manual and also try flushing a lot more water but I bet its the duckbills as you suggest. I need to become familiar with servicing them anyway as we are moving aboard next fall. Im thinking of setting up a salt water flush option for the forward head to use when on passages and concerned about freshwater use. Overall I have been totally sold on the vacuflush system. I do need to learn how to service it and plan to carry spares but my whole family loves the thing. Especially the kids who are too small to pump a manual head.

[SV Demeter]

One other thought. If I am going to get into replacing duckbills is there anything wrong with running a gallon or two of vinegar through the system to try and clean a bit before I have to get into the nasties?

[peghall]

Nothing wrong with doing that, but you shouldn't need vinegar in a fresh water system...a half a cup of Dawn or other liquid detergent in a bowl full of water through it, followed by another couple of bowlfuls of clean water, should be all you need to do to clean it up.

You really should go to the sail show...you can prob'ly pick up the duckbills (you'll need 4 for the vacuum pump...get two more for the overboard discharge pump) as well as an owners manual. And learn a lot about all the systems on your boat from the various mfrs and vendors too. Thursday and Monday are the best/least crowded days to go. Thursday is VIP/press day, tickets cost more, which keeps the crowd down...worth the extra money IMO. Unless it rains. If it does, crowds are smaller any day, but they're all jammed into the tents...making it very obvious who's had a bath that day and who hasn't had one for a while!

[SV Demeter]

Originally Posted by peghall

Nothing wrong with doing that, but you shouldn't need vinegar in a fresh water system...a half a cup of Dawn or other liquid detergent in a bowl full of water through it, followed by another couple of bowlfuls of clean water, should be all you need to do to clean it up.

You really should go to the sail show...you can prob'ly pick up the duckbills (you'll need 4 for the vacuum pump...get two more for the overboard discharge pump) as well as an owners manual. And learn a lot about all the systems on your boat from the various mfrs and vendors too. Thursday and Monday are the best/least crowded days to go. Thursday is VIP/press day, tickets cost more, which keeps the crowd down...worth the extra money IMO. Unless it rains. If it does, crowds are smaller any day, but they're all jammed into the tents...making it very obvious who's had a bath that day and who hasn't had one for a while!

Ha ha thanks Peg. I have an exhibitors pass for the show with BVI yacht sales. As most years will probably end up spending way too much money at the show...

[psneeld]

Or even easier...get rid of the vacuflush...buy a couple of inexpensice macerator pumps...mount them under the toilets with enough pipe to hold a flush or two and pipe the effluent to the holding tank.

WAYYYYYY cheaper...easier to troubleshoot...quieter (at least my installation is). The vacuflush toilets are just like the RV gravity drop ones so the plumbing is similar and simple

[Chief Engineer]

Peg....shaving cream........I learn something new every day.....

[richardhula]

Duckbill valves will probably fix the problem but use double hose clips back to back with 180° offset on connections each side of pump. Warm hose with hairdryer before tightening.

[peghall]

Originally Posted by richardhula

Duckbill valves will probably fix the problem but use double hose clips back to back with 180° offset on connections each side of pump. Warm hose with hairdryer before tightening.

Warming a hose makes it easier to get it off a fitting...also makes it a lot easier to get it onto one...especially if the hose is lubed with K-Y.

Ok, boys...grow up! K-Y is a water soluble surgical lubricant, which makes it an ideal lubricant to use on hose connections and any other connection that you don't want to remain permanently greasy. MUCH better than dish washing liquid, which is the what the industry recommends.

Shaving cream........I learn something new every day....

So do I, Chief...so do I.