Many people call a macerator a saniflo. Saniflo is the name of the best known company for making toilet "loo" macerators, the word macerate means to "make like liquid." Loo macerators are used in places where it would be difficult to put a normal Loo, like in a basement where you would need to pump the loo waste up against gravity to the waste pipes or in a loft conversion where drain pipes may be on the other side of the house.
When installed and used correctly a macerator will normally give years of trouble free use, but like any other item it can go wrong for many different reasons.
If your macerator starts to go wrong there are many symptoms that you might see, if the unit starts to hum but will not flush the waste away you should try to isolate the unit from the electric by turning it off, plugging it out, or removing the fuse if you can safely do so, leave it off for a hour and then reconnect it to the mains, if this has not cleared the problem, isolate the unit again, try not to leave the unit humming even if that means calling a engineer immediately as leaving it on and humming and not working could burn out the motor, vastly increasing the repair costs
If the unit is leaking water out of the sides, again if safe to do so you should isolate the unit and call a engineer, only with this problem you should not turn it back on and only try to isolate the unit if you are 100 percent sure the electrical point as not become wet
And if the unit comes on by itself and then goes off, you should check that the loo over flow is not active or defective and also all taps that have a drain that lead into the unit are off and not dripping and if your washing machine waste connects into the unit, the water inlet valve on your washing machine is not defective, you can check this when your washing machine is turned off, pull out the soap draw, carefully use a bit of tissue and dry around in the area where the soap draw came from and then check that it as not got a constant drip of water from the top going down into the machine, here it could get very technical talking about the workings of a washing machine.
If you think there is a drip and it is constant and your macerator is coming on constantly you may need a washing machine engineer to fix the inlet valve, but this is very unlikely as your washer machine should have a non return valve or raised pipes at the back to stop this problem from occurring.