Macerator Failure

[Stu Jackson]

I'm unclear on the concept:  Blew a 30A breaker?  It's a 12V DC motor.  What 30A breaker?

[Peggie Hall]

It's a breaker on a 12v circuit that's rated to carry 30 amps....which is not that much on a 12 v circuit. 

The Raritan Crown Head actually draws 36 by itself. That gawdawful Jabsco "conversion" draws 24...the the average sea water macerating toilet draws 15...the LectraSan/ElectroScan draws 30+.   And then there's the fridge, which is a REAL power hog!

The Jabsco macerator pump draws 16. It SHOULD be on its own dedicated circuit--and so should any electric toilet--but often isn't, so if anything else on the same circuit is on at the same time, it can do one of two things--1. cause the motor to "lug"  (running an electric motor on low voltage is the quickest way to destroy it) or...2. blow the breaker.

[Ken Juul]

Stu understands electricity.  I think his question was more along the lines of what 30amp fuse?  If memory is correct, the standard electrical panel of that vintate boat only has a 20amp CB feeding the macerator and a couple other circuits.

[Stu Jackson]

That's correct, Ken.  My macerator is on its own circuit, all by its lonely.  While I'd have to go check, I doubt the fuse is more than 15 A.  Why?  'Cuz I ain't got no 30A glass fuses and I have replacements for everything.  Shurflo macerator, yippee

[Ralph Masters]

My fuse is a glass 15A, I know, it blew once when I closed the overboard first.  I had spare 2, 5 and 10's onboard, but no 15's.  I do now.

Ralph

[Indian Falls]

My macerator pops a breaker in the panel, which is not a fuse, it has the button that pops out.  (fairly certain it's 30amp) 

Who knows what was done in twenty years before I got this boat... it certainly has had some changes made that I am slowly finding and fixing. 

Peggy makes a good argument for tossing it on the dock.  It's just hard to take what looks like a brand new item and toss it overboard....  It's not hurting anything being there in working order.   I may be able to use it someday right?  Who knows, I just might take a long ocean trip in the next few seasons .

[Peggie Hall]

But it's NOT in working order...read your own last post...a bucket isn't a holding tank...and you do NOT want to wire it directly to the battery. Even if you could get it to work now, it won't be after it spends a few more years "resting."   

I know Stu knows electrical...I figured he just had a brain burp.   And btw...if you only have a 15 amp fuse or breaker in a circuit that has a macerator that draws 16 amps not even counting any startup "surge," wouldn't you blow a lot of fuses or breakers?

[Stu Jackson]

Since I use it regularly, no.  We're going out to the Farallon Islands tomorrow, 25 miles out.  I'll use it and report back on the definitive fuse size and nameplate rating of our equipment on Monday.

[Stu Jackson]

Didn't go to the islands, weather outside the Gate was foggy and there was only a little wind outside.

I did check the macerator fuse.

It is 20A, says so right on my 1986 electrical panel.  I did not check the nameplate on the pump itself.

Guess I do have a 20 A fuse replacement on board.

It is NOT 30A.

Really.

Sounds like Peggie is right about the 16A motor.

[Indian Falls]

I'm not throwing a perfectly good, bench tested, macerator away because of a bad connection, switch or even a bad circuit breaker. 

The thing about forums is you put down what happened to you and then someone else inputs their experience and soon there is a consensus in a topic that just might save someone a lot of trouble.

If I pull it, plug it, I can't use it anyway...  won,t really help the next guy get to the bottom of his problem.

When I find the culprit I'll post it and  t h e n  I'll decide whether or not to run around with a macerator on the Great Lakes.  It took me a year to pull the Loran out of my boat after it went obsolete.

Here's a question for the macerator users:  If you don't open the thru-hull and run the macerator does it slow down a lot, a little, no difference or blows your circuit breaker?  Can you turn it on off for 1-2 seconds with the thru-hull closed with no ill affect?

Thanks!

[Peggie Hall]

When I find the culprit I'll post it and  t h e n  I'll decide whether or not to run around with a macerator on the Great Lakes.

Don't go into Lake Champlain! NY and VT state law make it illegal for any vessel on Champlain even to have any sanitation plumbing except a toilet intake connected to a thru-hull. And they do enforce it.

If you don't open the thru-hull and run the macerator does it slow down a lot, a little, no difference or blows your circuit breaker?  Can you turn it on off for 1-2 seconds with the thru-hull closed with no ill affect?

Running dry for a couple of seconds at a time prob'ly won't harm the motor or blow a breaker...but it certainly won't do the impeller any good. If you do it enough times, it'll wear enough off the edges of the vanes to prevent it from pulling anything through it...and then you'll get to try to figure out why a macerator with an impeller that LOOKS just fine runs but won't pump anything. 

...and soon there is a consensus in a topic that just might save someone a lot of trouble.

Unless that someone is someone who'd refuse to give up a Loran for a year after Loran was turned off!  You were sure that if you waited long enough, they'd turn it back on..right? 

[Indian Falls]

I fail to see the concern with damaging the impeller, here's why:



The air in the discharge hose will compress to an extent and with tank contents a mere 1" away that impeller is going to get hold of something.  Under normal use I'm certain it takes more than 2 seconds to stop it when you hear that it has finished with your holding tank.  Not forgetting that the interior of the the septic system is a fairly humid place. The impeller  c o u l d  be dry depending on certain things but I'm certain that it will be wet enough. 

I also know that when you open your macerator sea-cock and your tank is empty lake water will fill the macerator and your tank if left that way long enough.  So there is a way to wet the impeller should the concern warrant it. 

Before Peggy can jab me with a smiley in disguise, make sure the sea-cock is closed at all times unless 3 miles from shore etc. etc...

I didn't "refuse" to pull the Loran...  it just took a year... and that comment was more of joke than a reality.

[Stu Jackson]

I didn't "refuse" to pull the Loran...  it just took a year... and that comment was more of joke than a reality.

I took even longer - earlier this year!

Seems you're right about the macerator, 'cuz it takes more than 2 seconds to shut it off once the pitch changes when the tank is emptied.  I simply ain't that fast anymore...

[Ralph Masters]

I flip off the switch and let a bit of water back flow into the tank to clean out the "pump" body, maybe three to seven seconds worth.  Like I said ealrier, I blew a fuse once closing the valve first.  I'd rather have a bit of water back flow in then blow a hose against the pressure of the pump.  But that's just me.

Ralph

[Peggie Hall]

I fail to see the concern with damaging the impeller, here's why:

Every time you turn on ANY impeller pump, it takes a second or two--sometimes even longer--to prime. Even in just a second of running dry before it primes, the dry friction heat from that wears a microscopic amount off the edges of the vanes every time...and the more li'l micro amounts that disappear, the less and less efficient the pump becomes at pulling anything through it. Sooner or later it'll stop pulling anything through it. It's kinda like a toilet that hasn't ever even had a new joker valve, much less been rebuilt...it still works...the users just don't realize how much better it used to work till it quits. 

That doesn't only apply to macerator pumps...it's true of ALL impeller pumps. Which is why impellers should be replaced at least every couple of years as PREVENTIVE maintenance. And why impeller pumps shouldn't be run dry repeatedly, even for a few seconds at a time, to test 'em.

But it's YOUR boat, your problems to solve or exacerbate or ignore...all I can do is advise, based on about 25 years of experience. Whether you take my advice or not is entirely up to you.