Never assume that the graduations on an induction hopper are correct.

To calibrate the graduations on the induction hopper:

• make sure the hopper is level;

• use a one or five-litre calibrated jug (one litre is equal to one kilogram);

• add known volumes to the hopper, marking the levels as the hopper fills;

• continue this process until the total capacity, to the point of run-off, has been determined; and

• mark this full capacity (volume) on the side of the hopper.

Once the hopper has been calibrated, the hopper capacity can be used to check the inflow meter accuracy when connecting to different water sources. If the hopper becomes damaged or misshapen, repeat the process to ensure the calibration is still accurate.