jambed maserator

[Captain Larry-DH]

Good day Peggy.
(Background) Back in March you responded to a post I had on a jambed macerator pump. I haven't had any cruises to Canada so haven't replaced it but this last week the old one started leaking at a crack in the pump housing which was found in the usual way. Open the boat and get overpowered by the smells coming from within and yes of course we had out of town guests with us! I asked everyone to go away and come back in a couple of hours and headed to the pump out. A complete pump out and flush followed by some of your wonderful KO I bough years ago and we were able to have a wonderful day on the water (with limited fluid intake) ;>)
Now I need to replace the macerator and have a few questions. I am interested in installing a diaphragm pump.

1. Do you have any suggestions for diaphragm pumps (manual and electric) or at lease models to avoid?
2. On the 1988 Catalina 30 factory install, the 1½"ø tank outlet has a short section of hose connected to a "T" fitting with the other cross arm of the T going to the deck pump out fitting and the stem of the T attaching to the macerator. there are no valves. should there be?
3. The 1"ø outlet hose is connected to the below waterline through hull with about 12" of hose that connects to the Marlon through hull ball valve. There is no vented loop. Do I need to add one? The ball valve is always closed unless I am pumping and I usually have it wired closed unless I am up in Canada.
4. My wife is dubious about "stuff" going through a 1"ø hose if it hasn't been chopped up by a macerator first. Any words of wisdom for her in that regard?

Hayden, she spells it Peggie. (Not Peggy). Little things count.

I’ve been using an older version of Dometic Sealand T Series Waste Discharge Pump for 8 years to replace the original macerator pump. I never bothered to enlarge the discharge to 1.5” but used a reduction fitting from 1.5” hose to the original 1” thru hull. I was concerned the back pressure would kill the output valves but so far so good. I think one might conclude after 8 years that “it works “ even though it’s not recommended by the pump maker.
Tell your wife not to worry about chunks - (unless someone literally shits a brick) it’s fully mashed and smashed by the time it’s been pumped through the head and sitting in the holding tank for a while, then pumped again through the diaphragm pump. I also see what goes through the clear section most pump-out hoses have, and what comes out of the holding tank is pretty soupy.
I think the marine industry should abandon macerator pumps and switch to diaphragm style - way more reliable. Yes, a diaphragm pump is more expensive, but it’s worth extra money to avoid replacement expense, a filthy job, and to be able to discharge reliably so your crew can use the head when needed.

 

[Captain Larry-DH]

Another tip - for users of electric discharge pumps: A key switch meets Coast Guard requirements for securing against accidental discharge. So you don’t need to use zip ties or wire on the thru-hull valve if you have a key switch (with key removed and valve closed).

 

[Hayden Watson]

I had the strangest maserator failure I have ever heard of. After I found that it was leaking between the pump housing and the impeller base at the motor, I proceeded to flush the tank as best as possible to prevent more odoriferous leakage. After the tank was flushed from the inside using a spray nozzle in the cleanout port in the top of the tank, I designed to back flush down the pump out hose. After a couple of flushes, the pump started leaking very badly. I found that all four of the machine screws that hold the pump housing to the impeller plate were broken and the macerator fell apart. I have no idea how the bolts got broken. Several months ago I had tried to turn the motor shaft with a screw driver but it wouldn't budge so I gave up on it but that was on the motor end of the macerator and the broken screws were on the pump end. I am just glad that it didn't blow out with a full tank. As it was there was just enough spill to make a 6"ø puddle and that made enough stink to make it almost impossible to work down below until a good breeze aired it out below for a while.

 

[RoyS]

Those bolts have broken on mine also. Poor design throughout. You will not discover those until you have purchased the repair kit. After that you go back and buy the whole replacement pump. While there you ponder buying a second spare pump to keep on board as a back up. Then you look in your wallet...

 

[JamesG161]

I had the strangest maserator failure I have ever heard of.

All Centrifugal type pumps develop torque to pump the fluid.
That torque force first twists the pump mounts [ pump head screws]. Then, if they hold strong, that torque force is applied to the motor and then transmitted to the motor mounts to the boat.

In the case of a Macerator Centrifugal pump, extra grinder vibrations are in essence pounding those pump head screws.

I recently replaced my Macerator with an "in kind" Jabsco. I read that old Jabsco's had your type failure and they corrected that design. Also their old macerator blades failed too [my failure] which in turn destroyed the pump impeller.

IMHO the worst place to have that design failure, at the pump head seal. Also hard to inspect those screws.
Jim...

 

[JamesG161]

until you have purchased the repair kit

Repair Kit ≈$75 New pump ≈$100 [ yes Virginia there is a Santa...] West Marine Price match.
So now I have a spare motor.
Jim...

 

[Captain Larry-DH]

Those bolts have broken on mine also. Poor design throughout. You will not discover those until you have purchased the repair kit. After that you go back and buy the whole replacement pump. While there you ponder buying a second spare pump to keep on board as a back up. Then you look in your wallet...

Buy a diaphragm type and be done with those issues.

 

[JamesG161]

Buy a diaphragm type and be done with those issues.

Putting it simply...

Pumping Crap will always have Issues!

Pumping method aside.
Jim...

 

[NotCook]

Which was a nice break for me 'cuz I've spend the last 3 days installing a new computer...a job that's never taken me more than 6-8 hours before.

I feel your pain! I've just done the same thing, plus 2 new iPhones - talk about painful!

 

[Peggie Hall HeadMistress]

Thanks for the sympathy, Brian! I finally managed solve the last problem this morning. I'm not exactly a novice at this stuff...my first computer was a Commodore 128 in the late '80s, But I finally managed to fight Microsoft to a draw and I'm celebrating tonight by making a very large dent in a bottle of very nice cabernet!

--Peggie

 

[Rick]

I for one dont even get what he means by a jammed macerator? And I read his first sentence several times. At face value.. Clogged? Rusted together? No power? I understand a clogged macerator. I understand a, fried from being dry run macerator. Jammed? WTF? Maybe I just missed something. I have had a few clogs, and Peggy may get pissed but our best method for fixing that is normally a thorough pumpout at the station, maybe a top off of water just to get a complete rinse, and then a bunch of hot hot water which we let sit. Then just be patient with a few short pushes of the switch. Let it get in the line up at the macerator. Sort of boiling the solid. It has worked every time so far. Yeah its not sofisticated but... If then not, I will attack pulling stuff apart and perhaps a needless waste of good wine money. But in this case, the other fix is super well explained in the thread/

Just saying.

Cheers

 

[Ward H]

While I have a new Raritan Electric Flush head waiting to be installed, I don't have the time so the quickest way to a working head was to install a new pump on the old PAR head. I started using it about a week after being launched.
Then I started noticing the smell and found water with a strange white film on it, in the previously dry bilge.
I traced it to the macerator leaking. I had the same bolt failure mentioned above. On my boat the macerator is in line with the pump out hose.
I filled the area with blue shop towels and oil pads, unbolted the macerator, unscrewed it from the T fitting and used a 1 1/2" straight thread plug to close off the T.
The hose looks original so will replace with new white sanitation hose next spring.

I found that, despite the 1" discharge hose, the thru hull took a 3/4" straight plug to close it off. I think that means the thru hull is 3/4"?

 

[Hayden Watson]

I find it very strange that we have had 3 instances of the pump head shearing off the motor. As an engineer, that is not a failure mode I would expect. For the short term I did the same 1½"ø threaded plug repair on my C30. That way I can keep on sailing while I decide how to fix it right. Not planning any trips to Canada this year so can't use it anyway.