Another Vacuflush Question

[Slowmo]

Our boat has a pair of the older Mansfield Vacuflush heads. This is a 'component' system with separate vacuum accumulators and pumps for each head. The aft head works well, the pump cycles for about 20-30 seconds after flushing. The forward head is where my issue is. The pump (T12) always cycles longer, about 60 seconds, and sometimes (1/20 times) it won't shut off at all until I turn the breaker off. If do that and then turn the breaker back on after an hour or so, it is fine, i.e. doesn't start pumping again. If I turn the breaker on right away, it just starts pumping again. Also, when it's stuck pumping it really sounds like it is straining against the vacuum after a while. The system seems to hold vacuum, I left it a month turned off and it still had enough vacuum to flush without the pump being turned on.

I thought of the duckbill valves but why would it hold a vacuum if they were leaking? I also wondered about the pressure switch but wonder why it would work sometimes and not others.

Any others have this experience?

 

[Comodave]

Send Peggie Hall. The Headmistress a PM and ask for her guide to maintaining a vacuum head.

 

[caltexflanc]

Our boat has a pair of the older Mansfield Vacuflush heads. This is a 'component' system with separate vacuum accumulators and pumps for each head. The aft head works well, the pump cycles for about 20-30 seconds after flushing. The forward head is where my issue is. The pump (T12) always cycles longer, about 60 seconds, and sometimes (1/20 times) it won't shut off at all until I turn the breaker off. If do that and then turn the breaker back on after an hour or so, it is fine, i.e. doesn't start pumping again. If I turn the breaker on right away, it just starts pumping again. Also, when it's stuck pumping it really sounds like it is straining against the vacuum after a while. The system seems to hold vacuum, I left it a month turned off and it still had enough vacuum to flush without the pump being turned on.

I thought of the duckbill valves but why would it hold a vacuum if they were leaking? I also wondered about the pressure switch but wonder why it would work sometimes and not others.

Any others have this experience?

Haven't had the experience (had three of those same systems on our boat) but the pressure switch is the first suspect. Does the bowl hold water (suspect #2).
I'll leave it to Peggy to ID the actual perp.

 

[Tator]

Hell with the PM! We're having the exact same problem. On my list to tear in to soon, but any help would be appreciated. Duckbills are a year old. Holds water fine.

Tator

 

[HeadMistress]

The forward head is where my issue is. The pump (T12) always cycles longer, about 60 seconds, and sometimes (1/20 times) it won't shut off at all until I turn the breaker off. If do that and then turn the breaker back on after an hour or so, it is fine, i.e. doesn't start pumping again. If I turn the breaker on right away, it just starts pumping again. Also, when it's stuck pumping it really sounds like it is straining against the vacuum after a while. The system seems to hold vacuum,

You've described all the symptoms of a failed vacuum switch (it's on one end of the vacuum tank). The vacuum switch has a sensor in it that starts the pump when vacuum is lost...turns it off when the correct level of negative pressure (vacuum) is reached. There's a little rubber diaphragm in it that wears and weakens over time till it tears, and even a pinhole is enough to keep the pump running. Unfortunately you can replace just that li'l diaphram, you have to buy a whole vacuum switch assembly...and Dometic/SeaLand is VERY proud of it! You can only get it directly from one of their regionly "authorized service centers." Give 'em a call to find out where the nearest one is: 800-321-9886

Fortunately it's easy to swap out. That assembly at the end of the vacuum tank looks just like an inspection port...it threads into the tank just like one. Make careful note of which wire connects to which terminal on it before you remove them from the old cap...attach them to the right ones on the new cap, wrap the threads on it with plenty of teflon tape and thread it into the vacuum tank.

If the one on the other system is at least 5 years old, you might want to get two, 'cuz that's pretty close to their average lifespan these days.

When Dave suggested sending me a PM, he was suggesting you get a piece I've written called "VacuFlush 101" which explains how they work and how much water they really need to keep 'em working trouble free. It wouldn't help you or Tater solve or prevent this problem--parts wear out--but most people find it useful and I'm happy to send it to anyone who asks for it. It's best to send me a PM to ask for it 'cuz I need your email address to do so (no way to attach anything to a PM).

--Peggie

 

[rgano]

Yup, Peggy nailed it. Had the same problem after I pried the vac switch out of the vac generator when a clear round lens fell into my commode for an overhead LED causing a clog we could not ID. After finding the lens, I put the vac switch back in and had the problem you are having, no matter how I tried to adjust the knurled knob on the switch.

 

[Woodstock]

Rather than start another thread titled "Another Vacuflush Question" I thought I would tag on to this one.
I have two Vacuflush heads and both seem to function well with vacuum recharging after about 35-40 pump cycles, about 30 seconds. However they sound very different when recharging. One produces a relatively soft (quiet) pumping sound when building vacuum and the other sounds like it is hammering when making each pump cycle. Ideas as to what is making the pounding sound?

 

[Maerin]

One produces a relatively soft (quiet) pumping sound when building vacuum and the other sounds like it is hammering when making each pump cycle. Ideas as to what is making the pounding sound?

The noisy one probably has some slop in the rod between the motor gearbox and the bellows, or a bearing going out. There are replacement parts available. There could be some accumulation in the housing that's causing the bellows to bottom out.

 

[syjos]

There is a kit available to make the vacuum pump quieter.

It includes a new bellow and motor. Around $250 at Marine Sanitation in Seattle.

 

[caltexflanc]

In this eastern part of the country I have received very good advice and service from Environmental Marine in Ft Lauderdale. Always worth a call. https://www.environmentalmarine.com/

Oh, and by the way, I mentioned the pressure switch first as suspect #1. Nyah!

 

[HeadMistress]

If the vacuum pumps are in different parts of the boat, it could just be that one area reverberates more than the other. When vacuum pumps were "stand alone" equipment (before SeaLand combined the vacuum tank and pump into a"vacuum generator"), mounting the pump on a thick piece of foam rubber helped a lot. I have no idea how to insulate a reverberating vacuum generator...not sure that even the $250 kit syjos suggested would help that.



--Peggie

 

[Vactech]

Hi there.. take off the cover on the top of the vacuum pump, turn the pump on check to make sure that the pump securing screws are tight. If the pump is jumping or moving about. if it is nnot moving or jumping . It can also be as somebody mentioned that the Bellows is bottoming out ,either due to foreign product stuck in the pump housing or the Bellows is completely worn out and no longer able to function properly .my guess it is your Fasteners are loose. rebuild kit one of the members has mentioned in previous answer is known as The Whisper conversion kit .comes with motor, bellows, o rings ,and the half clamp seals. The motor is much stronger much quieter and much more efficient then the small old motors

 

[Vactech]

Addition to my previous post .highly recommend the conversion kit if the Fasteners are not loose.
I use these kits on a regular basis and cures most issues with the pump.
Very good value for its cost

 

[Woodstock]

Addition to my previous post .highly recommend the conversion kit if the Fasteners are not loose.
I use these kits on a regular basis and cures most issues with the pump.
Very good value for its cost

Thanks for all the great suggestions.
Now my biggest challenge is finding a 60# assistant that can get to the vacuum generators to do these things.

 

[Gordon J]

It does help

If the vacuum pumps are in different parts of the boat, it could just be that one area reverberates more than the other. When vacuum pumps were "stand alone" equipment (before SeaLand combined the vacuum tank and pump into a"vacuum generator"), mounting the pump on a thick piece of foam rubber helped a lot. I have no idea how to insulate a reverberating vacuum generator...not sure that even the $250 kit syjos suggested would help that.



--Peggie

I have replaced two older pumps with new quieter models. A big difference in noise level. If one is all of a sudden noisy, try flushing with a lot of water,. There might be an undigested peanut or some such causing the bellows to bottom out. This is how I fixed a temporary problem with a new quiet running pump.

Gordon