How do I diagnose Vacuflush

Hampton

Hampton

Air Defense Dept
TECHNICAL Contributor
Nov 26, 2006
7,628
Panama City, Fl
Boat Info
2008 44 Sedan Bridge
Engines
Cummins QSC-500's
Straight Drives
I've done searches, and I know there is already a ton of info here, but I couldn't find it. In my 18 years of owning Sea Ray Cruisers, I have never had any work done to any head system.

My Master head motor now runs and, apparently, does not build up vacuum. I had the dealer mess with the pressure switch, but I'm pretty sure that was a waste of money (no pun). It appeared that the problem was that the pressure switch was not sensing the vacuum and shutting off the motor, but now, I'm pretty sure it isn't building vacuum.

The motor seems quiet, as if it's not working too hard. The draw on the DC panel is not as great as when the other head motor is pumping. All indications are that the problem is the bellows then, right? If so, what do I replace while I do the bellows? The duck bill valves I assume? Do I automatically go for the motor? It seems fine.

What source do you all use for the parts?

Thank you.
 
I would start with duck bill valves and you can pull the bellows and make sure it is not packed with paper or goo…. I think you can see the linkage from the motor to the bellows, make sure it is still attached.
 
John, have you tried cleaning the ball and the ball seal in the toilet first? Might just be a bad seal there. Mine has an intermittent problem there that goes away for a while after I clean it. I just bought the new ball seal to install.
 
I keep a whole pump as as a spare and when I do a repair I install the whole pump. Then I renovate the old one by disassembling the pump in its entirety (easy, takes 5 minutes) and soaking it in a bucket of dilute muriatic acid to remove all scale. Install new duck bills and bellows (if necessary) and you have an as new pump again.

You could have bad duckbills and you could replace these with the pump in place. If you have never done any maintenance on your vacuflush for a few years then I would at least consider doing what I describe above. You will have a worry free vacuum pump then.

The bellows can be a bit tough to remove. I use a very large screwdriver through the crank, put my feet on the pump base and pull hard.
 
ZZ13 said:
John, have you tried cleaning the ball and the ball seal in the toilet first? Might just be a bad seal there. Mine has an intermittent problem there that goes away for a while after I clean it. I just bought the new ball seal to install.
Click to expand...
The symptom for the ball seal is that water won't stay in the bowl.




+2 on the duck bills...
 
JimG said:
The symptom for the ball seal is that water won't stay in the bowl....
Click to expand...

But it will also make the pump kick off periodically trying to rebuild the vacume.

If confident that the motor on the pump is good, I would replace bellows and dock bills. It's like inspecting an impeller. If you went through the trouble of taking it all apart to clean, considering the age of originals, just put new ones in.
 
Not wishing to be the bearer of bad news, but you may have an issue with the hoses. Last year I had similar symptoms with my system and discovered after replacing duct bills, seals and valves, that the hoses had developed several small leaks which prevented the system from obtaining a vacuum.

It turns out that Searay is having problems with the black hoses they used deteriorating not only in older models but also in boats only a few years old. I replaced mine with all new white sanitary grade piping and all is well after a significant lightening of the checkbook.
 
jrirvine1 said:
Not wishing to be the bearer of bad news, but you may have an issue with the hoses. Last year I had similar symptoms with my system and discovered after replacing duct bills, seals and valves, that the hoses had developed several small leaks which prevented the system from obtaining a vacuum.

It turns out that Searay is having problems with the black hoses they used deteriorating not only in older models but also in boats only a few years old. I replaced mine with all new white sanitary grade piping and all is well after a significant lightening of the checkbook.
Click to expand...

I had to replace my sanitation hoses last year due to cracks! The hose mfg supplied replacement hose at no charge and I paid labor to have them replaced.
 
John, second all the advice about checking the hoses; I've had to change out mine as well. The method I've used to verify that it's the hose and not anything in the pump assembly is to take off the input hose (output from the head), then seal off the input pipe (holding my hand over the input worked for me). Then have someone turn on the pump. if it builds up a vacuum and stops you will know it's the hose, assuming the head bowl is not leaking. If the pump doesn't hold a vacuum you will need to trouble shoot and correct that but do also check for a hose leak again (which I found out the hard way). The hose replacement if needed may or may not be an easy job. One of my sets was easy but the other was not real accessible and changing cost a lot of labor.
 
Frank, I'll call tomorrow. Thanks for the call.

Boat isn't 18. It's 6 years old.

Not the bowl seal.

Sounds like it could be hoses or bellows/duck bill.

Interesting note: When this first started happening, I would turn the Master Head switch off and let it sit overnight. In the AM, when I turned it back on, the light came on "Green" meaning that there was already a vacuum built up from the night before. This tells me that at that time (a couple of months ago), the hoses were good and the internal parts were good. The switch simply wasn't turning the pump off. I had the switch serviced.

Now, it doesn't seem to build up vacuum. I'm going to check it again tomorrow, then call Frank.
 
Thanks for the source. So, before I called Frank, I ran a ton of water through the system. Before I did, the pump ran freely and didn't seem to be working hard at all. After I ran the water, it built up pressure and ran normally and shut down normally. Sounds like (as learned from Frank), the duck bill valves are aging/drying out. That corner of the boat is in the afternoon sun. May have something to do with the early aging. I will buy the parts and keep available for that day. In the mean time, fluids only in that head.
 
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