Macerator Orientation

[Ray Squires]

Someone pointed out to me recently that the macerator on the H285 I bought was installed backwards (pumping seawater into the holding tank). We just cruise the inland bays, so we've had no use for it, and the prior owners were likely the same. I closed the seacock and re-oriented the macerator. To get decent hose runs I had to mount it with the intake pointing down. Is there a problem with this? If so what is a proper orientation? Thanks,Ray

 

[Peggie Hall/Head Mistress]

Macerator should be at or below tank discharge...

It should not be above the tank 'cuz that requires the impeller to run dry--which is how impellers get "fried" and quit working. I'm not quite sure what you mean by "the intake is pointing down"..but it doesn't sound good, and it may be necessary to move the macerator. And since it hasn't been used in some time, I'd also recommend that you replace the impeller as part of your spring recommissioning.If you're in doubt about which way is "in" and which way is "out," it's simple: on a Jabsco macerator, the intake fitting is 1.5" and the discharge fitting is 1".

 

[Dakota Jim Russell]

Peggie ???

My perception of the Hunter factory installation of a macerator on my 340 places the intake for the macerator above the bottom of the holding tank. So am I burning the impeller out when I run it to dry ???And how long should I try sucking that last bit out ?

 

[Peggie Hall/Head Mistress]

Depends on how long it takes to prime

Jabsco's instructions say their macerator shouldn't run dry for more than 30 seconds. However, every second that an impeller spins dry puts some heat friction wear on it that eventually takes its toll... so the closer to that maximum tolerance, the shorter the life of the impeller, and I don't like to see any installation that allows an impeller to run dry for more than 3 or 4 seconds.As for the last inch on the bottom of the tank, you'll never get it out. Once the level in the tank drops below the top of the discharge fitting, suction is broken and the pumpout or the macerator starts sucking air...so the longer you run the macerator trying to, the more damage you do the impeller in the macerator. There's no reason to get the last inch out...it just seems to be a psychological need...and I do NOT recommend installation a discharge fitting ON the bottom of the tank to accomplish it. Just pump enough clean water through the head while pumping out to dilute it.

 

[Ray Squires]

More On Orientation

On my 285, the discharge hose runs from the holding tank (under the aft berth, port side) over to the compartment under the starboard cockpit seat. At the bottom of that locker the hose T's, with one leg going to the pump out (starboard aft part of the cockpit). The other end of the T continues straight up about 6" into the suction of the macerator. This means the macerator is pulling straight up from the discharge hose, not straight up from the tank.