Holding tank will not pump out

[Bridgeman]

The fact you filled the vent pipe is likely a red herring. Your pump out just isn't working. That means a blocked pipe or a defective pump. Can suggest pump remedies if you tell us what sort of pump it is

Cheers jfm. Its a jabsco mascerator type. We will get pump out in next few days. Just found the filter or I guess that's what it is (photos attached) and other bits in the starboard cabin wardrobe behind bulkhead so not all bad news. Learning everyday.
rgds
Neil

 

[longjohnsilver]

I've got the Jabsco macerator pump. A few times it has stripped its impeller blades. On other occasions it refuses to actually pump, but from trial and error I've found that switching it on and off (and listening to a change in pump sound and gurgling) it will clear itself and pump like a goodun. There seems to be no rhyme nor reason for this, but that's the way it's been now for about 5 years. Sometimes i need to switch on and off say half a dozen times or more before it works.

Worth a try as you've nothing to lose before taking things apart.

 

[Bridgeman]

I've got the Jabsco macerator pump. A few times it has stripped its impeller blades. On other occasions it refuses to actually pump, but from trial and error I've found that switching it on and off (and listening to a change in pump sound and gurgling) it will clear itself and pump like a goodun. There seems to be no rhyme nor reason for this, but that's the way it's been now for about 5 years. Sometimes i need to switch on and off say half a dozen times or more before it works.

Worth a try as you've nothing to lose before taking things apart.

Thanks for that. I have tried a few times but will have another go tomorrow. As you say worth a try again before stripping everything down.

 

[IDAMAY]

We had exactly the same symptoms very recently with an over full tank, confirmed by removing the inspection plate - not a nice experience! However, using the shore pump out has remedied the problem. We put it down to either:

1. A blockage somewhere in the pipe work that has been removed/disturbed by the vacuum created by the pump out,

or

2. An air lock in the system cured by the same method.

Anyway, I suggest it is well worth trying the pump out before any more drastic approaches.

Best of luck - holding tank problems are some of the worst on boats!

Richard.

 

[Bridgeman]

We had exactly the same symptoms very recently with an over full tank, confirmed by removing the inspection plate - not a nice experience! However, using the shore pump out has remedied the problem. We put it down to either:

1. A blockage somewhere in the pipe work that has been removed/disturbed by the vacuum created by the pump out,

or

2. An air lock in the system cured by the same method.

Anyway, I suggest it is well worth trying the pump out before any more drastic approaches.

Best of luck - holding tank problems are some of the worst on boats!

Richard.

Thanks Richard. We have pump out arranged in next few days so will see how it goes.
Rgds
Neil

 

[jfm]

I hate those Jabsco impeller pumps. I prefer diaphragm pumps.

In your second picture the plumbing is odd. The smell filter in the vent line (green lid) is a vetus NSF38. I don't think that is fairline OEM but might be wrong. Anyway, if you have overflowed your tank thru the hull vent then the bottom loop of pipe twixt NSF and thru hull is now full of fluid. Nothing is going to clear it, so you have no vent, and your Jabsco pump will be struggling to pump against a vacuum and will eventually give up. That is likely what has happened, and if you have kept it running the impeller might have overheated and been ruined.

You absolutely must clear the fluid out of the big U of pipe in the vent line. If you do that, and if the impeller hasn't been damaged, then the pump will pump again. But remember the dockside pump out isn't going to clear that U. To clear it, just disconnect the upper jubilee clip (the one attaching the white pipe to the thru hull ). Nothing will spill out. Then lower the end of the pipe into a bucket to empty it. Job done. The thing should now pump again if the impeller hasn't been fried

So long as you never over fill the tank up the vent line you will get away with that form of plumbing, but it is not right and that big U is a totally unacceptable way to plumb this in my book.

You might well say that the design of the NSF forces you to have a U, even a small one. Yes it does if installed like that and in that case it is the wrong part and you should have the Leesan version instead. That NSF is intended to be mount ABOVE the thru hull for the vent, not below it as in your picture. You should relocate it there.

Is the vent pipe and Vetus NSF filter an OEM Fairline installation?

 

[Nigelpickin]

If it's a jabsco then there should be a screw you can turn at the end of the unit, (covered by a rubber cap). Turn it clockwise a couple of rotations to prime the pump. It will sound like it's working but doesn't mean that it is so that's the first thing to try.

Second thing is the replace the impeller and chopper, both will cause the pump to fail if they are less than 100 percent, (most likely the impeller). Jabsco do kits for these and they are pretty easy to dismantle, clean and replace...

We keep a spare jabsco on board and I've adapted the unit to be a snap in/snap out so when things go wrong it's a very quick swap and we have time to recondition the faulty unit.

If it's a block try working the sea cock while you pump out, this can cure the problem but it's probably the pump...

 

[Bridgeman]

If it's a jabsco then there should be a screw you can turn at the end of the unit, (covered by a rubber cap). Turn it clockwise a couple of rotations to prime the pump. It will sound like it's working but doesn't mean that it is so that's the first thing to try.

Second thing is the replace the impeller and chopper, both will cause the pump to fail if they are less than 100 percent, (most likely the impeller). Jabsco do kits for these and they are pretty easy to dismantle, clean and replace...

We keep a spare jabsco on board and I've adapted the unit to be a snap in/snap out so when things go wrong it's a very quick swap and we have time to recondition the faulty unit.

If it's a block try working the sea cock while you pump out, this can cure the problem but it's probably the pump...

Thanks Nigel I will put it on my list.
Rgds
Neil

 

[Bridgeman]

I hate those Jabsco impeller pumps. I prefer diaphragm pumps.

In your second picture the plumbing is odd. The smell filter in the vent line (green lid) is a vetus NSF38. I don't think that is fairline OEM but might be wrong. Anyway, if you have overflowed your tank thru the hull vent then the bottom loop of pipe twixt NSF and thru hull is now full of fluid. Nothing is going to clear it, so you have no vent, and your Jabsco pump will be struggling to pump against a vacuum and will eventually give up. That is likely what has happened, and if you have kept it running the impeller might have overheated and been ruined.

You absolutely must clear the fluid out of the big U of pipe in the vent line. If you do that, and if the impeller hasn't been damaged, then the pump will pump again. But remember the dockside pump out isn't going to clear that U. To clear it, just disconnect the upper jubilee clip (the one attaching the white pipe to the thru hull ). Nothing will spill out. Then lower the end of the pipe into a bucket to empty it. Job done. The thing should now pump again if the impeller hasn't been fried

So long as you never over fill the tank up the vent line you will get away with that form of plumbing, but it is not right and that big U is a totally unacceptable way to plumb this in my book.

You might well say that the design of the NSF forces you to have a U, even a small one. Yes it does if installed like that and in that case it is the wrong part and you should have the Leesan version instead. That NSF is intended to be mount ABOVE the thru hull for the vent, not below it as in your picture. You should relocate it there.

Is the vent pipe and Vetus NSF filter an OEM Fairline installation?

Thanks again jfm. That makes sense. definitely overflowed through vent. Something to watch in future. We bought the boat last year but would assume its original Fairline as only 4 years old. Will try your suggestion first.
Rgds
Neil

 

[jfm]

Thanks again jfm. That makes sense. definitely overflowed through vent. Something to watch in future. We bought the boat last year but would assume its original Fairline as only 4 years old. Will try your suggestion first.
Rgds
Neil

Ah ok. It doesn't look fairline. The jubilee clips are not doubled as Fairline would, and they rarely buy Vetus stuff. They do not afaik include a vent charcoal filter on sq42 at all, and when I have specced them they always fit Leesan. I therefore think you have an aftermarket install, done badly. If you overflowed thru the vent then for sure that massive U loop is full of fluid so the poor Jabsco pump isn't going to empty the tank. You need to have the vetus NSF raised up above the thru hull outlet

 

[Bridgeman]

Ah ok. It doesn't look fairline. The jubilee clips are not doubled as Fairline would, and they rarely buy Vetus stuff. They do not afaik include a vent charcoal filter on sq42 at all, and when I have specced them they always fit Leesan. I therefore think you have an aftermarket install, done badly. If you overflowed thru the vent then for sure that massive U loop is full of fluid so the poor Jabsco pump isn't going to empty the tank. You need to have the vetus NSF raised up above the thru hull outlet

Thanks for that. I will look into it. Strange changing the system though wonder what the reason was? As I said it worked smashing upto my slip up in overflowing, so makes sense about the water in pipe causing a vacumn.
Brgds Neil

 

[david_bagshaw]

Just to add to the above,

the seal on the jabsco macerator, can either wear or its spring break causing a small amount of air in , leading to loss of suction.

Along with worn impeller and leaking gaskets and the slightest loose jubilee clip.

Can you vent the outlet a bit otherwise not only does it have to suck up to the pump but also blow a large quantity down at a similarish head as well.

 

[jfm]

Strange changing the system though wonder what the reason was?

Not strange imho. A carbon filter in the vent pipe is a good* idea to stop smells outside when a WC is flushed. I have specced these on my boats for the last donkey's years. The problem in your case isn't the idea; it's the implementation

*Peggy Hall disagrees with them, but I don't buy much of her theory on venting

 

[Bridgeman]

Not strange imho. A carbon filter in the vent pipe is a good* idea to stop smells outside when a WC is flushed. I have specced these on my boats for the last donkey's years. The problem in your case isn't the idea; it's the implementation

*Peggy Hall disagrees with them, but I don't buy much of her theory on venting

Sorry jfm. I thought you meant the whole system was changed not just the filter added.
Im certainly learning a lot today. All the best. Neil

 

[jfm]

Sorry jfm. I thought you meant the whole system was changed not just the filter added.
Im certainly learning a lot today. All the best. Neil

No I meant just the big S shaped pipe and the green Vetus NSF filter have been added, and are not factory original. The rest I expect is factory original. There would have been an air vent in the factory installation but it would have had no vent and the 38mm white pipe would have gone directly from tank up to thru hull, with no U bend. Then previous owner must have asked someone to install a charcoal smell filter, and doing that incorrectly has created the big U bend, now full of fluid and in effect blocking your vent completely such that the poor little jabsco is trying to pump against vacuum which it can't do. Easy fix is move the green Vetus filter up above the thru hull so there are no U bends. You don't even need to buy any white pipe - there is so much of it!

 

[Bridgeman]

No I meant just the big S shaped pipe and the green Vetus NSF filter have been added, and are not factory original. The rest I expect is factory original. There would have been an air vent in the factory installation but it would have had no vent and the 38mm white pipe would have gone directly from tank up to thru hull, with no U bend. Then previous owner must have asked someone to install a charcoal smell filter, and doing that incorrectly has created the big U bend, now full of fluid and in effect blocking your vent completely such that the poor little jabsco is trying to pump against vacuum which it can't do. Easy fix is move the green Vetus filter up above the thru hull so there are no U bends. You don't even need to buy any white pipe - there is so much of it!

Thanks for the explanation jfm. It was my fault not reading your previous post correctly. I understand what you mean and will lift the filter. Hopefully doing this and also draining the pipe will solve problem, if pump not wrecked.
Brgds
Neil

 

[jfm]

Thanks for the explanation jfm. It was my fault not reading your previous post correctly. I understand what you mean and will lift the filter. Hopefully doing this and also draining the pipe will solve problem, if pump not wrecked.
Brgds
Neil

beware also that if you lift the smell filter you add extra pressure head to the tank if you ever over fill it again. If the tank is good it should be fine, but I'm just saying in case the tank is flimsy. You don't want the smell filter any higher than the bare minimum above the through hull.

 

[vas]

beware also that if you lift the smell filter you add extra pressure head to the tank if you ever over fill it again. If the tank is good it should be fine, but I'm just saying in case the tank is flimsy. You don't want the smell filter any higher than the bare minimum above the through hull.

John,

curious why the smell filter has to be above the skin fitting. I can understand the case for the particular filter where inlet and outlet is both facing down, but I guess it's not a general rule, is it?
I mean in my case I have a 200mm (or so) long smell filter with in-outlet on the two ends of the tube. Am I right in not having to have that higher than the skin fitting?

cheers

V.

 

[jfm]

John,

curious why the smell filter has to be above the skin fitting. I can understand the case for the particular filter where inlet and outlet is both facing down, but I guess it's not a general rule, is it?
I mean in my case I have a 200mm (or so) long smell filter with in-outlet on the two ends of the tube. Am I right in not having to have that higher than the skin fitting?

cheers

V.

Hi Vas. You're right - it is not a general rule. The smell filter does not usually have to be above the hull outlet, and on my boat (using Leesan smell filters) they aren't. But just with this particular Vetus smell filter it is necessary to have it above the hull fitting, due to the bottom outlets on the filter unit. If you do not mount this particular filter above the hull fitting then you must create a U bend, and a U bend is absolutely not acceptable in a black tank vent pipe (or in a fresh water or fuel vent pipe, for that matter)

 

[Bridgeman]

Just a quick update. I took breather/smell filter pipe off and emptied it of water (about 1 litre in bend of pipe). Pump still not working. We have ordered new pump. Can anyone see a problem putting new pump on before emptying tank ashore? is it better to empty tank before changing pump? I was concerned it may syphon back. Cant get a pump out ashore at present.
Thanks
Neil