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ranger58sb · 11-10-2012, 14:43

Quote:

Originally Posted by HopCar

Macerator pumps which use rubber impellers after the chopper blades should act as a closed valve. If the impeller or housing is worn I imagine there could be leakage. My tank is partially below the waterline and my pump (Jabsco) is below the waterline. Nothing flows back to the tank when the seacock is open.

Maybe that means I should check ours for wear

It's likely a Jabsco, and I've only used it once in about 7 years... and that was a few years ago...

-Chris

**Hudson Force** · 12-10-2012, 11:26

Quote:

Originally Posted by wingNwing

This looks like a simple system, but one caveat: how do you change out the macerator should it fail? ........................... in your setup as diagrammed, without the valve to isolate the macerator pump, replacing it would be an unbearable proposition as you would be doused with the contents of the holding tank.

I see your concern and it could be a serious problem. I have changed my macerator pump after a failure without a great mess. My effluent from the holding tank is at the top of the tank and the hose flows down to the macerator with a short, approximately 18" span. Though still a potential mess, I simply placed the entire broken pump in a tough plastic bag after disconnecting it from the through-hull side and removed the hose from the "T",- discarding this section as a unit with no spill or mess.

**Hudson Force** · 12-10-2012, 11:29

Quote:

Originally Posted by CapTim

dumb question... and I know I should know better, but I just can't get my brain wrapped around this one:

When the macerator isn't running, it acts as a valve in the 'off' position? So there is no chance of backflow from, say, the ocean to the holding tank?

My through-hull valve is always cloded unless I'm operating the macerator pump; therfore, no sea water would have any means of entering the system and the macerator end of the system would be fully blocked from any draw from the deck pump out. I don't actually depend on the inability for any reverse flow through the macerator.

rocksculpter · 12-10-2012, 12:22

Hmmmm, I can't remember if I put a valve between the tank and macerator, too many years since I put it there but that's a good point, what if the macerator needs work while on a cruise. I'd best check next time I'm at the boat.

What I wonder is if others have done what I did, put the discharge above the waterline which solves alot of potential problems.

Barry, Lopez Island

cal40john · 12-10-2012, 13:31

Quote:

Originally Posted by rocksculpter

Hmmmm, I can't remember if I put a valve between the tank and macerator, too many years since I put it there but that's a good point, what if the macerator needs work while on a cruise. I'd best check next time I'm at the boat.

What I wonder is if others have done what I did, put the discharge above the waterline which solves alot of potential problems.

Barry, Lopez Island

I used the existing through hull that was there for the toilet outlet before the holding tank existed.

I doubt that many have put theiroutlet above the waterline. Showing others what comes out, and stains on the hull. If you're doing it the absolute proper way the outlet would be above the highest point that the waterline would be when you heeled or they would say that you still need a vented loop.

John

**Hudson Force** · 12-10-2012, 15:03

Quote:

Originally Posted by cal40john

...............................or they would say that you still need a vented loop. John

Most would only open the through hull for an attended event. If that's your procedure, then you would have no need for a vented loop.

cal40john · 12-10-2012, 15:23

Quote:

Originally Posted by CaptForce

Most would only open the through hull for an attended event. If that's your procedure, then you would have no need for a vented loop.

I don't have a vented loop either. I only open the seacock to pump out. If I left it open 4 check valves would have to fail, but I have seen threads where people insist on the vented loop no matter what. That is why I used the word "they".

John