Complete the following two steps:
Watch video from 40secs-1min mark. This will show you how to clear the blockage in the grease trap.
If the cafe sinks are blocked you will need to follow this procedure with the Grease Trap in the grease trap room.
If the kitchen sinks are blocked you will need to follow this procedure with the Grease Trap under the sink. Then watch the 2nd clip on unblocking the Air Conditioning Drain