sealand s12 pump question...

garjowan

garjowan

Member
Jul 26, 2007
54
Newton, MA.
Boat Info
1987 SeaRay 340ec
Engines
Twin 454 IB's
having issues with my vacuflush system...
vacuum pump (s12) will not shut off.
I replaced the duckbills today and when apart there was a nice hard chunk of old TP stuck between the pleats of the billows...
Once all was back together, I expected the pump to run, build us pressure and stop...
NOPE, kept running and running and running... so much so, that the holding tank looked like it was going to explode.

One question is , what is the exact difference between sealand t12 and s12 pumps... both appear identical , yet cost several hundred dollars difference.

Thanks in advance!
Gary
 
garjowan said:
having issues with my vacuflush system...
vacuum pump (s12) will not shut off.
I replaced the duckbills today and when apart there was a nice hard chunk of old TP stuck between the pleats of the billows...
Once all was back together, I expected the pump to run, build us pressure and stop...
NOPE, kept running and running and running... so much so, that the holding tank looked like it was going to explode.

One question is , what is the exact difference between sealand t12 and s12 pumps... both appear identical , yet cost several hundred dollars difference.

Thanks in advance!
Gary[/QUOTE
Push on the knurled adjustment switch and see if the switch is close to opening. If slight pressure does not work make an adjustment. If that works you will need to check vacuum/why pump not building it
Click to expand...
 
don't know of any "knurled adjustment switch"... where is that at???
And, I'll recheck the fittings at the pump, I may have over tightened them causing the duckbills to "pinch up" and possibly create a air leak, but kinda doubt it...
Yes, the tank has always and still does hold water.
 
The pump will stop when there's enough vacuum in the vacuum tank. There's a switch there and this could be stuck and not working properly. Remove the cover and try to move it with your hand.

The T pump is actually a macerator and should be used to empty the holding tank. :wink:


vacuum.jpg
 
can't say I've ever seen a tank under there... going back to the boat this AM, I will look around.
 
garjowan said:
can't say I've ever seen a tank under there... going back to the boat this AM, I will look around.
Click to expand...

I believe your Sealand system should be like mine. The tank should be located between the toulet bowl and the "s" vacuum pump.
 
the system was originally a treatment system, o the tank could be anywhere i guess...
I'm thinking the bellows got cracked from being jammed with old TP...
I will rip it all apart again today and see where I'm at. :/

Side question, the "t" series is a bellows pump as well, just that it macerates too, can't that model pump be used in the place of the "s" model???
 
"T" for transfer. "S" for suction. The T-pump doesn't really macerate - it works with the same principle of the S-pump. I believe you could swap motors and possibly the bellows between the two. But the T-pump only uses one duckbill on each side - the body of the pumps are different. I thought the prices were about the same - but you can call the guys at Northeast Sanitation - they're a good bunch of people. You can also just get a rebuild kit...

But... I don't think the bellows is your problem - otherwise, you wouldn't be able to BUILD pressure - your problem is you're making TOO MUCH pressure. The note above about the pressure switch is likely the culprit. I take it your tank doesn't have an over-pressure release valve?
 
garjowan said:
NOPE, kept running and running and running... so much so, that the holding tank looked like it was going to explode.
Click to expand...

A holding tank should NEVER be pressurized!!!!!! Your vent line is restricted. You'll want to correct that immediately!
 
Ya the pressure in the tank issue is definitely going to be the vent, it's time to clear that out.
But, I am not building vacuum on the vacuum side, when I flush, I get basically gravity fed draining... There are no air leaks in the lines as far as I can tell...
Where the bellows in the vacuum pump is, is that not an airtight system,?
If yes, which would be how it builds vacuum, there has to be a split or crack in the bellows caused by the jammed paper, allowing the vacuum to escape... the duckbills are fine, the hoses are fine and the toilet is fine.
That leaves the bellows and/or the switch on the vacuum tank... yes I found the tank... lol!!!

As far as the "T" and "S" models go, if the only difference is one duckbill per side and macerating, can't I use the fittings from the "S" pump seeing as that is where the duckbills are housed?

And as far as rebuiling, the bellows are around $100, the o-ring kit is around $80, another set of duckbills are $30 and for $100 more I could get the whole assembly in a "T" model pump... And anywhere I've looked, the difference between the "T" and "S" are averaging $300! yikes!

But if the two can not be "interchanged", the new bellows is the start.
 
The "main" pump body is different so the fittings can't be interchanged. Keep in mind - there is no "macerating" - it is simply discharging.

You're right on the pricing difference - I called NE direct - I guess I was remembering wrong. Yeah, that is a huge difference! If your plastic pump body is good, there is not reason to buy a new S-pump.

Yes, it should be airtight.

Oh, and let me correct myself from above... a pressure relief valve is not for preventing pressure - it's for preventing vacuum (like on an aggressive pump out).

Like Coaster said, vent line is most likely clogged if you're experiencing pressure. Thinking more about this (sorry - had to run out quick earlier), your pressure switch is probably fine. It's running and running because you're not building vacuum - which leads back to a leak - and your thought of checking the bellows is spot on. Could also be the o-rings. FYI, on NE's site, $170 gets a bellows, duckbills and o-rings.
 
Thanks all for the help...
I have just ordered the rebuild kit, 4 duckbills, bellows and gaskets for $132 at seacoast services.
They were the best price I found, and great customer service.
I'll post up the outcome.... FINGERS CROSSED! ;)
 
No problem - good luck! Hope that solves your problem so you can get back to... well.... you know:lol:

The kit you got is for your model year? Only reason I ask is that NE had two kits available - one for "pre-1990" and one for "post-1990". The post '90 was about the price you quoted.
 
Ya thanks, it's the clamp style, pre 90's...
Of course it's more than the newer style...LOL
Luck o' the Irish I guess! ;)
Thanks agin, you've been a great help!
 
Was the system generating vacuum before you replaced the duckbills? Could the duckbills have been installed in the wrong direction?
 
Last edited:
The pressurized tank indicates that the valves and pump are functioning (if they were backwards, the unvented holding tank would be under a vacuum instead of pressure).

That vent really IS a serious issue! The air and liquid that's pumped out of the system has to go somewhere. Since it can't displace air in the holding tank, it has to compress it. It's like blowing up a balloon inside of a beer bottle, but instead of just maxing out the power of your lungs, in this case there's the added threat of exploding sewage.
 
RollerCoastr said:
The pressurized tank indicates that the valves and pump are functioning (if they were backwards, the unvented holding tank would be under a vacuum instead of pressure).

That vent really IS a serious issue! The air and liquid that's pumped out of the system has to go somewhere. Since it can't displace air in the holding tank, it has to compress it. It's like blowing up a balloon inside of a beer bottle, but instead of just maxing out the power of your lungs, in this case there's the added threat of exploding sewage.
Click to expand...

You make a good point - I hadn't considered that.
Here's another question - could the fact that the holding tank is not venting correctly be the issue in that the pump cannot displace enough air on the exhaust (holding tank) side to evacuate the air in the vacuum tank thereby tripping the pressure switch?
 
Absolutely! (particularly if the holding tank is on the full side - the less air there is to be compressed in that tank, the harder it will be to achieve a vacuum upstream)
 
While I was rebulid my vac-pump, I found the only thing that cleaned the crusty crud off the parts was muriatic acid.
Get a gallon form a hardware store or a good hull cleaner with the acid in it.
Let the parts soak a while, brush with an old tooth brush, rinse with clean water.
The parts will look brand new.
Just be careful with acid that will burn skin.

Best,
Mark.
 
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