vacuflush pump

vic33004

Active member
Joined
Jul 10, 2007
RO Number
27361
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1,552
i'm trying to track down a vacuflush leak issue. the pump on one of my systems runs every 5-10 mins and takes a long time to shut off. i've checked the seals on the head and they are not leaking. i've checked the seals on the pump and they are not either. i used shaving cream to verify this. the bellows is not leaking either. i did find that when i touch the pressure switch actuator it will turn off. so i'm suspecting that the switch is the problem. how do i verify that the switch is bad and is it the electrical end or the actuator end of the switch that gets replaced?
 
Usually the electrical end of the switch is fine, it s the rod that corrodes along with the seal inside the tank

It s easy to pull and check
 
i put shaving cream on the actuator/spring assembly and dont' see a leak there either. By the way the switch is acting when i touch it, the pump is either not getting the last stroke's worth of vacuum to shut it down or the switch is not sensing enough vacuum to shut down. the duck bills are less than 5 months old and i've flushed lots of water thru just to make sure its not debris hanging up on the valves.
 
They make a vacuum gauge that fits into the bottom of the head bowl to measure the vacuum the pump is pulling.

Also, while you normally don't have to do it, the throw of the rod that activates the switch is adjustable as I recall.

But in any case, it sounds to me like the switch contacts might be dirty or going bad.
 
It s really friction/corrosion on the rod in the tank which preventsnthe rod to be pulled far enough for switch to open

Sealand recommends against trying to adjust the spring setting
 
i spoke with the local dealer and he indicated that if the pump is cycling and taking a long time to shut down he thinks its a vacuum leak. there is one item that i've not replaced on the heads, the o rings on the ball shaft in the bowl. apparently dometic does'nt sell just the o rings. they sell a complete ball and spring set. i'm going to start with those o rings and see if that fixes the problem. sounds like if the switch is the problem i'm not much worse off by changing the o rings.
 
Pascal has tons of experience with VacuFlush heads; if it were me, I'd take what he says to be Gospel...!
 
Gospel? Gee Vic... We're talking toilets here... Lucky you didn't mention the quoran or you d have a fatwa declared on yr head:)

If the problem was a leak you d hear it as it would have to be pretty massive to make it hard for the pump to build enough vacuum. I ve has pieces of to stuck in bowl created a loud hissing yet the pump would vacuum and cycle on and off
 
assuming that i have to pull the pressure switch i've not found any part kits for repair or rebuilding them, it seems like the only option is to replace the entire switch assembly unless it went out of adjustment. the local dealer wants $50.00 just to check the adjustment if i bring the switch to them. does'nt sound like money well spent as it seems unlikely that its gone out of adjustment.

i def don't hear any kind of leak, nor can i find any. the dealer did suggest putting a plug in the vacuum generator to isolate it from the system and see what happens with the pump.
 
Pull the switch assembly and take a look.. I replaced one a couple of years ago it's easy. You ll see righ away if the rod is corroded or the membrane damaged

The bad news is that the whole assembly is $100+
 
quote:

Originally posted by PascalG

Sealand recommends against trying to adjust the spring setting






Not to contradict your holyness. :-)

But as I said, you normally shouldn't have to do it. It's just that I've encountered cases in the pasted where I have had to adjust the spring setting. And there was no corrosion on the rod.
 
ok, progress at last! changed the o rings on the ball shaft and both systems held vacuum overnight. i've owned the boat for 6 years and its never done that before! gosh how i love low cost solutions! FYI, Dometic does'nt sell just the 0 rings, they sell a complete ball valve and spring kit (about $38.00) the size of the o rings are 3/8 x 1/16 and are readily available in a hardware store. we'll see going forward if the pressure sensor still has issues on the one system.
 
Nice when it's a simple, and cheap, fix. :-)

Out of curiosity, did you happen to put shaving cream around the o-rings before you changed them? And if so did it show the leak?
 
glad it was simple! i'm a little surprised you didn't hear the leak though, usually they are audible even when small.

Sealand sells a lot of stuff as complete assemblie$...
 
Pascal, just commenting on my previous observations with your offerings on VacuFlush systems. You've been right a lot more times than you've been wrong.

I make it a point not to quote from the Koran, Quaran, Quoron, or however you spell it, because I don't want anyone making false assumptions about me. Plus, as you mentioned, fatwas are always waiting to be declared by someone with no sense of humor, just off in the shadows. If you mis-quote from the Bible, the worst thing that will happen is that you'll be branded as a fool and laughed at!

Have a great Holiday weekend everybody!
 
If you have these heads, and I have three, it is really worth while to get their purpose-built vacuum tester and methodically check the system on down the line per the manual. It's about 70 bucks and a huge time saver. These systems are very simple and easy to fix. I had an improperly installed (via a PO) system for the master head, and it still took three years to manifest itself. When I did the re-plumb, the tester was invaluable.
 
bill, to answer your question, no i could not test the O rings on the ball shaft as you have to remove the water valve and flushing arm to get them.

knowing this, going forward when i next have to change the ball seal, the o rings will be part of that procedure. very simple to do but you have to pull the bowl seat out to get to it. I'm not sure why i could not hear it leaking but based on the results I'm confident that i've got the problem under control now. too bad all the misc boat fixes aren't settled with a pair of O rings........lol.
 
Did you actually get your problem fixed and the pump has stopped cycling?
 
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