Final answer:
The low-side test pressure data plate value is used to determine a safe pressure for leak testing in refrigeration or air conditioning systems.
Step-by-step explanation:
The low-side test pressure data plate value should be used by a technician to determine a safe pressure for leak testing. This is because it provides the maximum pressure that the low side of the refrigeration or air conditioning system can safely handle without incurring damage or causing safety issues. Using this value, technicians can ensure they do not exceed the system's designed pressure limits during the leak testing process, which is essential for identifying leaks within the system.