can't pump out waste tank

peterwynndavies · Mar 17, 2022

Firstly the senders. These are sensors attached to the outside of the tank. The adhesive fails. I reattached mine with aluminium tape.
The other issue you have is either a blocked pipe or a broken / broken macerator. The thru hull on my 356 had a 90degree elbow just above it where shards of lime scale would accumulate. Shut off the thru hull disconnect and clear the pipe. If that's clear then I'm afraid it's the macerator. Take it apart and service it.
Wear gloves!

jviss · Mar 17, 2022

sabbatical88 said:
I don't see any discharge (yes, 2+ miles offshore).

That should be 3 miles, Captain.
boatwaste_bro.pdf - Hawaii.gov

Peggie Hall HeadMistress · Mar 17, 2022

Contrary to popular belief, opening the deck pumpout fitting cap doesn't provide enough air into the tank to notice because the other end of the pumpout line is at the bottom of tank. The best that might do is release any pressure in the tank.

The two most common locations for a vent blockage are the vent thru-hull and the other end of the vent line--that end of the hose and the vent fitting on the tank. Start by cleaning out the thru-hull...use a screwdriver blade, ice pick--whatever works. If that doesn't result in a spew out the vent, you'll need to relieve the pressure before removing the vent line from the tank to clean them out...so open the deck pumpout fitting VERY CAREFULLY with a hose at the ready. Be sure you're UPwind of it! Scrape out that end of the vent line and the vent fitting on the tank...reconnect the vent line.

If there's a filter in the vent line, remove it...once a filter gets wet--which can happen when a tank is overfilled or even due to heeling--the charcoal swells and blocks the vent...one of the reasons why vent filters aren't recommended for use on most sailboats.

Have you tried using a dock pumpout to empty either tank? If a pumpout can empty the tank, your vent isn't blocked. Does each tank have its own discharge pump (macerator or SeaLand T-Series pump), or do they both use the same pump? If it's a macerator pump, it's not generating any suction, which means it needs a new impeller. Worst case, if the line to the macerator pump hasn't been rinsed out by running plenty of water through it after each use, it may be blocked by sludge.

So the first thing you need to do is visit a pumpout to try to empty the tank. If you can't, that may mean a vent blockage or it may be a blocked pumpout line...but it would be highly unusual for both tanks to be un-pumpable for any reason other than a blocked vent.

It's a 20 year old boat...how long have you owned it? Is this the first time you've tried to empty the tanks? Did it sit for a long time before you bought it?

--Peggie

Windpilot · Mar 17, 2022

Macerater impeller is probably shot if the pumps more than a hand full of years old.
Easy to fix for about $40. Pumps above waterline so not that messy at all.
Solids blockage is possible, go to a pump out, pump out, refill, pump out, usually takes care of it.
Get new replacemt KUS sending units, probably for each and every tank you have. Length is important, should be stamped on the ones you have.
My experience only, yours may be different

smokey73 · Mar 17, 2022

First, see if your waste vent line is clear.
Like Peggy said, opening the waste pump out won't solve anything and may make it impossible to pump it out. At least on my boat, when the waste pump out is open, the macerator only pumps air and you can see the air coming out in big gulps but no pumping of liquid. I believe this is because the macerator suction is on the same line as the pump out line and that "short circuits" so that it only pumps air. There is a single line out of the tank (connected to a tube that goes to near the bottom of the tank) and then there is a T that splits to the pump out line and to the macerator. Hence moving air is easier than "lifting" waste so it only pumps air. Its that way on my boat anyway. That's my story and I'm sticking to it.

jviss · Mar 17, 2022

sabbatical88 said:
Thanks for the comments everyone, especially the "headmistress" (cute handle!). I found that the marina down the way has its pumpout station available again so I will go there first and try to pump out. I will try cleaning the thru-hulls next. Then vent lines and macerator impellers. I wouldn't doubt that the impellers are bad by now.

smoke73, thanks for the 1 tube Y valve explanation- makes sense to me

Peggie- I didn't understand "you'll need to relieve the pressure before removing the vent line from the tank to clean them out...so open the deck pumpout fitting VERY CAREFULLY" - Do you mean simply removing the pumpout cap on the deck, or something more? As you said the pumpout line goes to the bottom of the tank. So I think you mean to relieve air pressure from the top of the tank somehow, correct?

The boat had been sitting for a long time before I bought it about a year ago. I tried using the macerator before (3+ miles offshore), but I don't think it pumped out then either. There are 2 independent holding tanks and macerators.

thanks, John

I think Peggy means that if your tank is pressurized due too a plugged vent, you should relieve that pressure by opening the pumpout cap; but note that you can end up with a fountain of poop if the pressure is high enough. So, be careful.

Peggie Hall HeadMistress · Mar 17, 2022

I didn't see any mention of a y-valve--which is definitely needed !-- in smoke73's post, only a tee fitting.

Snake River Electronics--a brand that went out of business more than 15 years ago--supplied the tank level monitors to Hunter when your boat was built. They never did work properly, partly because Hunter techs failed to follow installation instructions. Today, SCAD tank level monitors--which also have sensors that attach to the outside of the tank--are top rated and very reasonably priced. Scad Tank Monitors Available from a number of sources including Amazon.

On another note...you said your toilets are VacuFlush systems. Those work very differently from typical manual or electric toilets. I've written a piece I call "VacuFlush 101" that explains how it works (an amazing number of owners think they do, but don't...the reason why 75% of the marine toilet problem posters on the net are VF owners) and how much water it actually needs to keep it working trouble-free. I'll be glad to send it to you if you (and anyone else who'd like to have a copy) along with the VF troubleshooting guide would like to send me a PM that includes your email address (no way to attach anything to a PM).

--Peggie

smokey73 · Mar 17, 2022

@Peggie sent you a pm.

bawlmer · Mar 17, 2022

Danger Will Robinson!!! Having a 2003 boat makes your macerator(s) almost 20 years old. You should replace the macerator(s) before the bolts rust away and deposit poop like substances into your bilge. Ask me how I know this. Also my macerator failed years before it rotted out. I cruise the Chesapeake so the macerator was a non starter so I stupidly did not pay attention to it. My money is on a broken macerator(s). Fair warning.

jviss · Mar 17, 2022

bawlmer said:
Danger Will Robinson!!! Having a 2003 boat makes your macerator(s) almost 20 years old. You should replace the macerator(s) before the bolts rust away and deposit poop like substances into your bilge. Ask me how I know this. Also my macerator failed years before it rotted out. I cruise the Chesapeake so the macerator was a non starter so I stupidly did not pay attention to it. My money is on a broken macerator(s). Fair warning.

Wow, that stinks!

My macerator stopped working last season. I don't even know where it is! Seriously, I can't find it. The boat's a 1996, so I should locate it and probably just take it out, maybe replace it with one of those manual diaphragm waste pumps. I really never use it, anyway.

Peggie Hall HeadMistress · Mar 17, 2022

sabbatical88 said:
@peggie I would like a link to your article on vacuflush heads.

It's not a link, it's document that can only be sent by attaching it to an email. Since few people want to post their email address publicly, I ask anyone who wants it to provide your email address to me privately.

--Peggie

bawlmer · Mar 20, 2022

jviss said:
Wow, that stinks!

My macerator stopped working last season. I don't even know where it is! Seriously, I can't find it. The boat's a 1996, so I should locate it and probably just take it out, maybe replace it with one of those manual diaphragm waste pumps. I really never use it, anyway.

Yes. Should locate it and replace it or at least carefully inspect it. It will rot out whether you use it or not. I remember somewhere the manufacturer (Jabsco) upgraded the bolts to a decent quality of stainless steel but I do not recall what year.

jviss · Mar 20, 2022

bawlmer said:
Yes. Should locate it and replace it or at least carefully inspect it. It will rot out whether you use it or not. I remember somewhere the manufacturer (Jabsco) upgraded the bolts to a decent quality of stainless steel but I do not recall what year.

Yes, I'm not afraid of sinking the boat, as the seacock for it is always closed, but if it breaks apart it will spill sewage into my bilge!

Peggie Hall HeadMistress · Mar 20, 2022

jviss said:
My macerator stopped working last season. I don't even know where it is! Seriously, I can't find it. The boat's a 1996, so I should locate it and probably just take it out, maybe replace it with one of those manual diaphragm waste pumps. I really never use it, anyway.

So much of New England waters are NDZ that you can't get enough use out of either type of "tank dump" pump to make it worth the price to buy it and the cost and time to maintain it--something it doesn't sound like many of you have been doing anyway--so I'd just get rid of it.

bawlmer said:
Yes. Should locate it and replace it or at least carefully inspect it. It will rot out whether you use it or not. I remember somewhere the manufacturer (Jabsco) upgraded the bolts to a decent quality of stainless steel but I do not recall what year.

It's illegal to dump a tank anywhere in the Chesapeake Bay, so you're another one who might as well jus locate and remove the macerator pump 'cuz you can't use it.

--Peggie

jviss · Mar 20, 2022

Peggie Hall HeadMistress said:
So much of New England waters are NDZ that you can't get enough use out of either type of "tank dump" pump to make it worth the price to buy it and the cost and time to maintain it--something it doesn't sound like many of you have been doing anyway--so I'd just get rid of it.

--Peggie

Thanks, Peggy. Probably the best option.

bawlmer · Mar 20, 2022

Peggie Hall HeadMistress said:
So much of New England waters are NDZ that you can't get enough use out of either type of "tank dump" pump to make it worth the price to buy it and the cost and time to maintain it--something it doesn't sound like many of you have been doing anyway--so I'd just get rid of it.

It's illegal to dump a tank anywhere in the Chesapeake Bay, so you're another one who might as well jus locate and remove the macerator pump 'cuz you can't use it.

--Peggie

I know. That was my first thought. My mechanic told me it would seriously ding the resale value of my boat so there lies my conflict. I am planning to sell the boat.

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