Macerator not working

[5teve]

Hi Guys

Looking for Ideas - I have retro fitted a holding tank to the boat - 25mmm out from TMC electric toilet to tank - 38mm with dip tube to macerator via a short pipe then to 25mm out to thru hull

also have 38mm pump out and 2x 25mm vents

Just wired the macerator up - switched on with around 3.5" water in the tank (should be plenty) and the pump starts - slows down and then pops the 20A breaker and pumps nothing - not a drop. I assume its not priming but being a new pump - cant work out why - I'm also reluctant to remove the pump as it was an absolute S**t getting the pipes on so my best bet would be to cut the pipes!

Any ideas what to look for? - Pump is an Aquatrack macerator (Jabsco copy) should pump 45l/min - Picture of part complete install below

 

[NormanB]

Sounds like it is jammed with something or other. Would drop the macerater out and check free to turn by hand and if not then investigate further.

 

[jfm]

Put an ammeter on it and confirm it is pulling too much current. If yes then it is jammed or something as NB says

But if you want an easy life chuck that pump away. It's rubbish and you'll forever be fixing it. It's is above the tank so as soon as impeller gets worn it won't prime. Fit a diaphragm pump instead like sealand T series and you won't regret it. You'll need 38 not 25mm pipe twixt pump and seacock, and 38mm seacock, though. That's the only way to do a black tank system properly in this size of boat imho.

 

[longjohnsilver]

Hi Guys

Looking for Ideas - I have retro fitted a holding tank to the boat - 25mmm out from TMC electric toilet to tank - 38mm with dip tube to macerator via a short pipe then to 25mm out to thru hull

also have 38mm pump out and 2x 25mm vents

Just wired the macerator up - switched on with around 3.5" water in the tank (should be plenty) and the pump starts - slows down and then pops the 20A breaker and pumps nothing - not a drop. I assume its not priming but being a new pump - cant work out why - I'm also reluctant to remove the pump as it was an absolute S**t getting the pipes on so my best bet would be to cut the pipes!

Any ideas what to look for? - Pump is an Aquatrack macerator (Jabsco copy) should pump 45l/min - Picture of part complete install below

View attachment 68022

Been there done that. To get the pipes on and off easily I heat them with a hot air blower normally used for stripping paint.

I'd take the pump off and try it pumping water from a bucket and see if that works. Are you certain the outlet pipe and seacock are open and clear? Try using a dinghy pump to either clear any blockage or to confirm all ok when you hear the bubbles exiting the hull.

 

[5teve]

Hi guys

Sorry this is a new install so pump is not jammed it's turning based on the sound and the fact it slows down until it pops the breaker, and pipes are all new and not blocked.

Diaphragm not an option at the moment as it's not coming out of the water for a while yet, the configuration is commonly used and the pump can prime to 4ft, it only has to manage 1ft so should be able to manage

Seacock definitely open... But will try and get air pump on to confirm its not blocked (toilet pumped out direct ok last week)

 

[simonfraser]

If the pump is already malfunctioning without any black content i’d be replacing it with something better, as #3.

 

[jfm]

Hi guys

Sorry this is a new install so pump is not jammed it's turning based on the sound and the fact it slows down until it pops the breaker, and pipes are all new and not blocked.

Diaphragm not an option at the moment as it's not coming out of the water for a while yet, the configuration is commonly used and the pump can prime to 4ft, it only has to manage 1ft so should be able to manage

Seacock definitely open... But will try and get air pump on to confirm its not blocked (toilet pumped out direct ok last week)

I'm saying your pump is rubbish and you should change it and you're defending it. Yet it's not working. Go figure! Yes the configuration is commonly used, in crummy substandard installations. It is not commonly used in properly specced boats. You'll be changing that excuse for a pump, and the only question is whether you do it now or whether you faff about a lot longer wasting time and then change it. I take yr
point on lifting the boat but for now you can run a 38mm diaphragm pump thru a 25mm seacock and only change to 38mm when you next lift the boat.

 

[Portofino]

Is it wired up the right way round ?
If so next step crack open the pump and check the impeller
You should carry a spare anyhow - look at it - source one.
Should all be 38 mm btw

 

[kashurst]

new tanks aren't always cleaned out properly - sounds like something has been sucked up and jammed the pump. There are better designs of pumps available but what you have there should work fine for quite a long time.
as per previous post, hot air gun on the hoses to warm them through and they come off easily - do the same putting them back on.

you will probably need to take the pump body apart to get out what ever is in there - there is usually a stainless steel blade in there so watch your fingers;-)

 

[jfm]

If you were to be changing a few things you might also consider taking the opportunity to replace the white 38mm hose with the proper butyl lined odour free hose. That white stuff lets smells through.

 

[CLB]

Could it be voltage drop. Have you spec' the wiring correctly? Those pumps draw quite a bit and need a good supply.

 

[Montemar]

If the motor runs then slows down and stops it seems that something must be blocking the input or output pipes. The trip/fuse will go because the stalled pump is drawing too much current when the rotor is no longer turning. The latter suggests the current capacity of the wiring is OK.
The short running time suggests a vacuum may be building up somewhere. Is there a vent for the tank? Has the piping collapsed internally?
Have you omitted to remove a blanking plug or somesuch?

 

[Freeloader]

I had the same symptoms on my last boat and spent loads of time trying to find a phantom blockage, whilst also replacing various parts and hoses. In the end I binned the (still quite new) pump and replaced it but still had problems with the new unit. However, by removing the input hose and putting a bucket of water under the pump, it immediately sprang into life and ran normally. On re-attaching the input hose, the pump emptied the tank. After a period without use, though, the problem would come back and I would have to manually re-prime the pump for all to be well again. Although supposedly self-priming, the 1' head was either too much for it or it was simply that the impeller would dry out and fail to self-prime.

On my current boat, I have a similat setup but it seems to work fine!?!? However, when I fitted a new service kit back in the spring, the pump failed to prime so I dismantled it again and wetted out the impeller, after which it ran without fault all season long. As your system is new, therefore, it may be that you have a similar priming problem. As suggested above, just try running it in a bucket to wet out the impeller and see if it then works normally afterwards.

If you still have no joy, I think the diaphragm pump idea certainly has merit. I would definitely consider going down this route if I ever need to change my pump again in the future...

 

[Portofino]

We have a similar pump -Jabsco I believe.
Having read JFMs posts and ,Freeloaders ^^ ,I thinks it’s all an installation issue .
Ours is in the depth of the V below the WL ( seacocked exist ) and crucially below the holding tank .

So thinking about it ( see Free loaders post ) it’s always wet primed ready to go —— which it does btw - no hassle at all .
It’s either wet from seawater or black water if the tank is near full and boats attitude stern down / bow up .

So reposition the pump lower than the tank and more or less level with the through the hull fitting .
We have not had any trouble with our pump ,but the bogs have macerators too so stuffs chopped twice so to speak before the rubber impeller .
I did on a board day strip it down n service / fit a new impeller ——— just for fun :encouragement:
Was thinking if we go off on an adventure anchoring off etc - needed to know how it worked incase it ended up a show stopper on day 1 or what ever .I didn’t !

 

[longjohnsilver]

We have a similar pump -Jabsco I believe.
Having read JFMs posts and ,Freeloaders ^^ ,I thinks it’s all an installation issue .
Ours is in the depth of the V below the WL ( seacocked exist ) and crucially below the holding tank .

So thinking about it ( see Free loaders post ) it’s always wet primed ready to go —— which it does btw - no hassle at all .
It’s either wet from seawater or black water if the tank is near full and boats attitude stern down / bow up .

So reposition the pump lower than the tank and more or less level with the through the hull fitting .
We have not had any trouble with our pump ,but the bogs have macerators too so stuffs chopped twice so to speak before the rubber impeller .
I did on a board day strip it down n service / fit a new impeller ——— just for fun :encouragement:
Was thinking if we go off on an adventure anchoring off etc - needed to know how it worked incase it ended up a show stopper on day 1 or what ever .I didn’t !

I can imagine the scene on Christmas morning in the Portofino household, after the Christmas dinner when everyone wants a bit of entertainment, MrP announces he's off to strip his macerator, and does anyone else want to join him, its such wonderful fun, they can all have a go. And as a special Christmas treat they could also take the inspection hatch off the holding tank and have a go at cleaning it out.

Oh what joy!

 

[Momac]

Pump is an Aquatrack macerator (Jabsco copy) should

Perhaps a real Jabsco pump would have been a better investment.
Sure its wired /plumbed the right way ? Does the pick up pipe go all the way to the bottom of the tank and if so is the suction causing the pick up pipe to seal against the base of the tank when power is applied?

 

[5teve]

Hi Guys

Just a quick update - We have had family over for Xmas and new year so been too busy to post..

Anyway Freeloader was on the money - The pump wasnt priming as it looked like it had dried out (even though its meant to prime dry) a small amount of water dropped in via a cup was enough to make it work and several times since (how quick does 150l fill up with 6 on board!)

I appreciate all the comments, good and Bad - I appreciate that the diaphragm pump is the way to go, however having bought a new pump I still have an expectation that it should work - albeit not for long

Pump is positioned where it is so that it does drain so replacing wont be as messy as it could be. From the research I did the most common theme was always have all entrys and exits coming in from the top (unless gravity emptied of course) which is why it is the way it is (wrong or right) - I just need to extend the dip tube as its a bit too high so leaves around 40l in the tank..

The good news is that it worked very well over Xmas dealing with 6 persons over a few nights while at Rottnest Island, shame we had a fight with a reef that has now put the boat on the hard and caused some head scratching regarding parts availability. Cause of the bingle was a combination of wind (25+knots) too tightly packed bay with boats swinging all over the place and avoiding another boat which swung back towards us - It looks like the insurance is paying anyway - but not something I would want to repeat - 38km return journey on one engine in 25+knots wind was not my highlight of the trip.. especially as the engine is now having voltage and revs issues now (think the low voltage (8v) under start is preventing the stop solenoid from retracting fully - apparently quite common) so next job is heavier wiring, shorter wiring and cleaning up all the terminals - then carry on troubleshooting!

Steve

 

[5teve]

We have not had any trouble with our pump ,but the bogs have macerators too so stuffs chopped twice so to speak before the rubber impeller

Yep ours is the same so its already a slurry by the time it gets to the tank.. and even more so when released!

Steve