Q = When the students are weighing out small amounts of chemicals into a beaker on the balance, the mass is either not registering at all or it is registers briefly but then the display returns to zero. Is this a fault or can it be adjusted?
A = This sounds like the auto-zero function, which is designed to re-zero the balance automatically when there may be a small increase/decrease in value on the pan caused by temperature change, dust, draughts etc.
The problem is that it also re-zeros the balance when you are trying to weigh very small amounts. See the help sheet 'CHANGING THE ZERO TRACKING TO ENABLE' and follow the instructions to resolve the issue.
Using the instructions, go to setup F4 and set ZEO to 0. The balance should now work correctly.