My Sealand Vacuflush doesn't work

CoronCoron

Member
Apr 13, 2020
206
Boat Info
Sea Ray 290 Sundancer, 1998
Engines
(2) Merc 5.0 EFI
I bought this 1998 Sea Ray 290 Sundancer recently and it used the have a very clear vacuum sound whenever the toilet was flushed. A week ago the vacuum sound did not happen, only the sound of the water pump putting water into the bowl.
So instead of using the toilet, I have test flushed it since and about every 8+ flushes the vacuum sound happens, while every other time the water simply fills the bowl more.
Before I pay hundreds to have the system serviced, any ideas to what I should do?
The holding tank is empty.
All ideas are welcome!
 
Look up on the Internet duck bill replacement for your VacuFlush pump (mine is a VG-4). Also, lookup toilet seal for VacuFlush toilet. Easy-ish repairs, but nasty, but I good skill to have...
some things to check:
Do you hear the pump (vacuum pump, not water) running after you flush? If yes, does it ever stop?
If no pump, the you need to find out why. if pump is running, and doesn’t stop, then you have a vacuum leak. Do the duckbills and seals, you need to do those anyway, since it is new.
if the pump runs, then stops, but no vacuum when flushing, then you have a blockage between the toilet and tank. Look at https://seacoastservices.com/how-it-works/ for an overview of how it works and all the parts to purchase....
 
This is a very complete answer, thank you very much. I will follow through on these ideas.
The only sound I hear now is the water pump. I was hearing the vacuum flush periodically maybe once every 8 flushes and now as I am testing it the vacuum hasn't sounded for some time.
So the vacuum pump does not run.
I will study the link that you have included.
 
If you look at the holding tank it has 2 parts, vacuum tank, and larger holding tank. They can be mounted separately, or together. You should see a hose coming from the direction of the toilet Into the Vacuum tank. If you remove the hose, and the head system is on, the vacuum pump should run, if you cover the hole (I covered it with my hand covered by a thick rubber glove) the vacuum pump should eventually stop, and you will feel the vacuum build up. if the pump still doesn’t run, then address that by checking for voltage at the pump, or remove it, wire it directly to 12 volts, and see if it will run.
 
A simple way to check for blockages is to pack a wet towel in the head at the bottom of the bowl, open the ball valve, and put a water hose around the towel. Hold it tightly so the water pressure can push any blockages to the tank.
 
If you look at the holding tank it has 2 parts, vacuum tank, and larger holding tank. They can be mounted separately, or together. You should see a hose coming from the direction of the toilet Into the Vacuum tank. If you remove the hose, and the head system is on, the vacuum pump should run, if you cover the hole (I covered it with my hand covered by a thick rubber glove) the vacuum pump should eventually stop, and you will feel the vacuum build up. if the pump still doesn’t run, then address that by checking for voltage at the pump, or remove it, wire it directly to 12 volts, and see if it will run.
Very good - next time I'm at the boat I will try this. If there is vacuum, what does it tell me - that there is a blockage between the head and the vacuum tank?
 
Very good - next time I'm at the boat I will try this. If there is vacuum, what does it tell me - that there is a blockage between the head and the vacuum tank?
If you have vacuum, AND the vacuum pump shuts off, then connect everything again, and the pump should run again. if it stops (30 seconds usually), but still no vacuum when flushing, you have a blockage.
if the vacuum pump does not stop, you have a leak, so repLace the toilet seals and the ball & shaft below.
If the pump does not run, verify voltage, replace pump. Based on symptoms, since you get a vacuum every so often, the pump appears to run. There is a pressure switch as well, it detects the pressure change and when no vacuum, it turns on pump. If that is broken, maybe never turns pump on

EA1E1BCE-49B4-4FE0-B28A-1F093C7201A2.jpeg
 
So I went down to the boat yesterday (Saturday) and the first test flush WORKED - vacuum was there and all was good. The next flush after a half hour or so had NO vacuum, but the "bottom valve"? opened fine and drained the water.
In the next 6 hours I test flushed another 10 times and I got vacuum 4 times, with the other 6 having the "bottom valve" opening and draining the water.
Isn't the vacuum supposed to happen every time?
If so, what does this periodic vacuum indicate?
Obviously it makes me not want to take a dump, let alone have guests use the head.
 
So I went down to the boat yesterday (Saturday) and the first test flush WORKED - vacuum was there and all was good. The next flush after a half hour or so had NO vacuum, but the "bottom valve"? opened fine and drained the water.
In the next 6 hours I test flushed another 10 times and I got vacuum 4 times, with the other 6 having the "bottom valve" opening and draining the water.
Isn't the vacuum supposed to happen every time?
If so, what does this periodic vacuum indicate?
Obviously it makes me not want to take a dump, let alone have guests use the head.
You have to tell us what the head pump is doing. You will hear the water pump turn on to pump fresh water, but once you release the foot pedal, it should stop in a few seconds. You should hear the head pump run, usually about 30 seconds(?) after flushing, then it stops. Does it keep running, or does it turn off? Yes, you should have a vacuum every time.
The periodic vacuum could be several things, if the pressure switch is failing, it might not be telling the pump to turn on all the time. If there is an intermittent leak, that could do it as well..
 
You have to tell us what the head pump is doing. You will hear the water pump turn on to pump fresh water, but once you release the foot pedal, it should stop in a few seconds. You should hear the head pump run, usually about 30 seconds(?) after flushing, then it stops. Does it keep running, or does it turn off? Yes, you should have a vacuum every time.
The periodic vacuum could be several things, if the pressure switch is failing, it might not be telling the pump to turn on all the time. If there is an intermittent leak, that could do it as well..
The head pump always came on for about 30 seconds each flush. Yes, the water pump is one for only a few seconds after each flush.
The pressure switch idea sounds like a reasonable answer - is there a way to test it or is it the answer to what I am experiencing?
 
The head pump always came on for about 30 seconds each flush. Yes, the water pump is one for only a few seconds after each flush.
The pressure switch idea sounds like a reasonable answer - is there a way to test it or is it the answer to what I am experiencing?
The pressure switch would be the answer IF the pump does not come on after a flush. Since it sounds like it is coming on after every flush, then turning off after 30 seconds, it seems to be working properly. A clog in the line might be able to cause this, but would have to be random which seems unlikely.
 
The pressure switch would be the answer IF the pump does not come on after a flush. Since it sounds like it is coming on after every flush, then turning off after 30 seconds, it seems to be working properly. A clog in the line might be able to cause this, but would have to be random which seems unlikely.
The vacuum only comes on every 4 or 5 flushes. Most times the "bottom valve" opens and drains the unit, without the vacuum sucking it out.
 
The vacuum only comes on every 4 or 5 flushes. Most times the "bottom valve" opens and drains the unit, without the vacuum sucking it out.
Right, but the head pump, which generates that vacuum, comes on after every flush, and shuts off after 30 seconds right? So the pressure switch is detecting a lack of pressure, and the pump builds it back up. If the pressure switch was cutting the pump off too quickly, before enough vacuum was built up, then the head pump would sometimes run for 5 seconds (little to no vacuum), and sometimes 30 (good vacuum), etc.
 

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