Do you see an orange light when you try to turn on the uroflowmeter? Then the batteries are empty.
Do the following:
See here how to open and close the battery lid to replace the batteries. Pay close attention to the "I" and "II" markings! The uroflowmeter works on 4 standard AA batteries. If you rent the uroflowmeter, make sure you return the original batteries upon return.
