Replumbing and relocating macerator pump

[John Langford]

Further to the excellent exchange on holding tank replacement I thought there might be some interest in my recent replumbing and relocation of the macerator pump - at least on the part of owners who are allowed to have a macerator pump.

While replacing all the original black Shield sanitary hoses with new expensive smooth walled white stuff from West Marine I decided that I didn't like having hose at the lowest point in the system leading to the macerator pump. My sense was that most of the smell came from this hose as it was always in contact with the stuff in the bottom of the tank. So I replaced the hose from the tank to the macerator pump with solid ABS black plumbing pipe and fittings. Here is how I did it. A 1 1/2"ABS coupling connects the T at the bottom of the tank to a short piece of pipe then a 90 degree coupling which leads to a second short length of pipe and two couplings that allow me to go back to a 5" length of  hose and onto the end of the Jabsco macerator pump. I also moved the pump up off the hull so that it is located almost level with the top of the tank and attached to a cedar block on the inside of the settee base. This would facilitate replacing it without a mess if it ever failed. It is Murphy's Law that the pump will fail when the tank is full and a pumpout station is nowhere to be found.

BTW, I also noticed that the tank is not evenly supported underneath. I have used a piece of cedar cut to size to support the whole of the aft end of the tank. Not perfect but it will do until I have to pull the tank. I also intend to redo the teflon tape on the inspection port. With the help of the deity I will beat back the evil pong!

[windrunr]

My macerator pump just failed and will need to be replaced. The pump case is rusted and I am unsure of the manufacture. If any one knows what model was installed on the 1987 boats.  I was thinking of installing Jabsco Macerator Pump. What is your opinion on the type of pump I should procure.

I am planning on taking John's advise on replacing the lower hose with ABS pipe.


Thanks

Rod Sparks

Wind Runner 
1987   Hull #291

[Ron Hill]

Rod : The macerator is a self-priming JABSCO #18590-0000 12V waste pump.
Remember the tip I wrote about.  If you think the macerator may be jammed - reverse the wires (for a moment) and see if the backward rotation clears that jam.  A thought.   

[Roland Gendreau]

When I serviced my jabsco mascerator pump recently, I noticed that the maintence instructions have this note:

Troubleshooting:

Pump does not start:

Impeller bound up:  - Insert screwdriver in slot of shaft at motor's rear end bell and rotate clockwise.

That would be an easier way of freeing the shaft than disconnecting and reversing the wiring!

The mascerator pump on my 1992 is model 18590-1000

Roland Gendreau
Gratitude #1183

[Ron Hill]

John : I hope that you saw one of my previous posts that mentioned placing a CUT OFF between the tank and the macerator pump!!!   Sure would save a mess when/if you ever have to remove the pump in the future.     

[lutherk]

Rod : The macerator is a self-priming JABSCO #18590-0000 12V waste pump.
Remember the tip I wrote about.  If you think the macerator may be jammed - reverse the wires (for a moment) and see if the backward rotation clears that jam.  A thought.   

You can also turn the pump shaft at the top with a screw driver - eliminating the need to fool with the wiring.

[John Langford]

Ron notes that you can put a cut off valave in the line so that you can work on the pump without having the contents spill into the bilge. I actually had a large bronze ball valve in the line in my original setup but removed it in favour of the  approach of raising the pump up to the level of the top of the tank. It makes for a simpler system with fewer couplings and makes it impossible for someone (me for instance) turning on the macerator with the ball valve closed.

[Ron Hill]

John : GREAT idea, as long as the macerator pump has enough "head" to pull up the stuff from the holding tank!! 
With the pump at the height of the tank you've accomplished the the same objective -- 
Keeping the stuff in the holding tank while you work on the macerator. 

[John Langford]

The jabsco macerator pump claims the ability to pull a prime and run many feet (up to 9' I recall)above the holding tank. This arrangement asks very little in that respect. I have tested the system and it pulls a prime almost immediately.