Vacuflush help

T

TimHenn

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I haven't had a single issue with either of my Vacuflush units until now. I tried going through the troubleshooting steps from the manual but I'm still not certain which issue i have. I thought if I posted the specifics, one of you vac-u-flush-experts could weigh in with some additional tests to run and/or help isolate the mostly likely cause.

Here's a picture of the unit I'm having trouble with for reference https://www.dropbox.com/s/t4lcsi6q0fi84mb/stbd-vacuflush.jpg

- Port unit works fine
- Stbd unit takes water in, but no vacuum is present.
- I shorted the sensor switch with a wire and the unit engages but I think it's just pumping air.
- After shorting the switch there IS a vacuum at the head but only for 1, maybe 2 flushes, then back to no vacuum.
- I've read about replacing a Bill Valve but have no idea if that's the problem and where those valves are.
- If it's a clog, what's more likely -- the input elbow or the output from the pump to the tank?
- I haven't run a snake into the hose after the head but I could.
- If it's the sensor switch (where I shorted) how to determine that versus a clog?

The unit worked fine two weeks ago though it didn't get that much usage.

Thanks for the help,
Tim
 
Well there only would be vacuum for about one flush each time the unit is flushed if everything is working properly. So it's no surprise that you only get one flush out of it where you force it to make vacuum.

When you manually make vacuum does the system hold vacuum? If so for how long?

You say you think the unit may be clogged. But when you make vacuum manually does the head flush properly? Or does it act clogged?

The duck bills are located on each side of the diaphragm vacuum pump.
 
>> When you manually make vacuum does the system hold vacuum? If so for how long?
Yes, it appears to work normally. The flush includes the sound of vacuumed air and all goes down as expected. The vacuum seal seems to be normal as well, in other words, the ball valve in the head is properly sealed so I would think the vacuum would hold till next flush. I didn't wait 5 or 10 minutes to test this though. The system automatically rebuild a vacuum in a few seconds so the next time you flush you get the same vacuum sound/action. That doesn't happen unless I force it via the switch.

>>You say you think the unit may be clogged. But when you make vacuum manually does the head flush properly? Or does it act clogged?
The only reason I would be after a clog is based on the troubleshooting information. It doesn't act clogged to me - the water goes down even without the vacuum reasonably well and when the vacuum is forced, it works as expected. Does that sounds like the sensor is faulty ??

Edit:
Found a good step-by-step for the duck bill replacement, but, I'm still not sure which problem I have
http://www.dometicsanitation.com/QBank/EPiServer/SeaLand/Manuals/Replacement-Parts/Vacuum-Generator-Duckbill-Valves_6420.pdf
 
If it is a clogged before the accumulator the pump will labor more because vacuum has already been established. It could be clogged after the tank but I would expect the pump to labor or hydrostatic lock after several pumps? If the switch is gone, the pump will not labor and vacuum will be generated when jumped. Given it seems the pump runs normally when the switch is jumped I'll bet it's the switch.
Without vacuum in the system the waste will pile up in the lines until good vacuum pulls it to the accumulator. Then when you flush again you will hear it all move.

If the pump does not run for a normal cycle after a flush it's the switch. If it runs on and on but there is no vacuum there is a leak or bad valves.
Are you jumping it to extend the pump cycle?
 
Its looking like its the switch -- how does the switch work? Originally, I was jumping the switch just to make sure there was power and the pump hadn't 'seized.

The water goes down when flushed so I doubt there's blockage there. When i force the pump to work I can see the air pulsing in the holding tank so it doesn't appear clogged there either -- the pump doesn't labor as best I can tell in any scenario. I noticed that when I was trying to remove the cover to jump the wires the switch engaged and the pump started briefly...maybe a loose connection? Or is there an adjustment to whatever triggers the switch to engage?

It's one of the more expensive parts in the unit, so, I'm just making sure I get the right thing.

Thanks,
 
Sounds like you need to clean the switch connections first and check the condition of the switch wires and wire connectors as well. If everything is good there then it sounds like it's the switch.
 
- Port unit works fine
>> irrelevant if they are on different pumps / vac gen

- Stbd unit takes water in, but no vacuum is present.
>> water comes from your fresh water system thru a simple valve! not affected by vacuum

- I shorted the sensor switch with a wire and the unit engages but I think it's just pumping air.
>> well it s a vacuum pump, it is supposed to pump air, mostly,..:)

- After shorting the switch there IS a vacuum at the head but only for 1, maybe 2 flushes, then back to no vacuum.
>> thre can only be vacuum for one flush

- I've read about replacing a Bill Valve but have no idea if that's the problem and where those valves are.
>> if when bypassing the switch you get vacuum it s unlikely to be the duck bills. Th duck bills are at the pump inlet and outlet, two of them. Clearly shown in the manual

- If it's a clog, what's more likely -- the input elbow or the output from the pump to the tank?
>> can be anywhere... First check the bottom of th head where the Venturi is, by holding the pedal down. If you don't see anything there it could be at the elbow coming into the vac tank. Either way, the pump will build vacuum into the tank and shut down.

- I haven't run a snake into the hose after the head but I could.

- If it's the sensor switch (where I shorted) how to determine that versus a clog?
>> if you bypass the switch manually for about 30 seconds and then it flushes right, it s not clogged but the switch, if after bypassing the switch you don't hear air when flushing, and water just sits there, it s a clogged.

Note that you don't have to bypass or short the switch, you can just pull on th rod to trigger switch, if you have a clog this is an easy way to increase vaccum and possibly clear it. This happened to me recently,ll we had guys polishing marble floors and they flushed paper towels, which got stuck in the hose... I manually coerced more vaccum by holding the rod and that was enough to suck the paper towels thru...
 
I can't figure out how to embed an image so here is a picture of what I have used many times to clear a minor clog...if the pump runs.

https://www.dropbox.com/s/ylfqankgt5kx5hy/Unplugger.JPG

Cut off water supply, empty bowl, hold pedal down to open the exit hole, turn the pump on and stick this thing down there tight and start pulsing dock water through it.
 
That is clever. I would work to back flush AC water lines as well . :D
 
quote:
Originally posted by Doc

I can't figure out how to embed an image so here is a picture of what I have used many times to clear a minor clog...if the pump runs.

https://www.dropbox.com/s/ylfqankgt5kx5hy/Unplugger.JPG

Cut off water supply, empty bowl, hold pedal down to open the exit hole, turn the pump on and stick this thing down there tight and start pulsing dock water through it.

--------------------------------------
There's a joke waiting there, somewhere.

Click to expand...
 
to the OP, it is very unlikely you have a clog between the head and the vacuum pump as the port at the bottom of the head is much smaller in diameter than the 2" line connecting the head to the pump.

my advice is to go after the low hanging fruit first. next to the vacuum pump will be a vacuum switch, these can fail over time and its easy to see if the switch is bad by simply bypassing the switch and see if the pump is working.

if you have not changed the duck bill valves yet, start there. they are located on the in/out side of each vacuum pump and there are 4 on each pump. they are in expensive and easy to swap out.
 
quote:
Originally posted by PascalG

- Port unit works fine
>> irrelevant if they are on different pumps / vac gen

- Stbd unit takes water in, but no vacuum is present.
>> water comes from your fresh water system thru a simple valve! not affected by vacuum
-------------------------------------------

And there you have it. Methodical, logical approach to your questions.
- I shorted the sensor switch with a wire and the unit engages but I think it's just pumping air.
>> well it s a vacuum pump, it is supposed to pump air, mostly,..:)

- After shorting the switch there IS a vacuum at the head but only for 1, maybe 2 flushes, then back to no vacuum.
>> thre can only be vacuum for one flush

- I've read about replacing a Bill Valve but have no idea if that's the problem and where those valves are.
>> if when bypassing the switch you get vacuum it s unlikely to be the duck bills. Th duck bills are at the pump inlet and outlet, two of them. Clearly shown in the manual

- If it's a clog, what's more likely -- the input elbow or the output from the pump to the tank?
>> can be anywhere... First check the bottom of th head where the Venturi is, by holding the pedal down. If you don't see anything there it could be at the elbow coming into the vac tank. Either way, the pump will build vacuum into the tank and shut down.

- I haven't run a snake into the hose after the head but I could.

- If it's the sensor switch (where I shorted) how to determine that versus a clog?
>> if you bypass the switch manually for about 30 seconds and then it flushes right, it s not clogged but the switch, if after bypassing the switch you don't hear air when flushing, and water just sits there, it s a clogged.

Note that you don't have to bypass or short the switch, you can just pull on th rod to trigger switch, if you have a clog this is an easy way to increase vaccum and possibly clear it. This happened to me recently,ll we had guys polishing marble floors and they flushed paper towels, which got stuck in the hose... I manually coerced more vaccum by holding the rod and that was enough to suck the paper towels thru...

Click to expand...
 
Thanks for the help. I returned to the pump and tried one more test - under the switch, I depressed the rod that is spring loaded which should engage the switch without shorting across the terminals (the way I see it) but it didn't work. So, I checked one more time that shorting engages the pump and it does. So, I pulled the switch and ordered a new one. I think that should do it. Hopefully I won't need the duck valves as well but should probably purchase a few pairs for the future.
 
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