Final answer:
A pressure relief device should be installed on the discharge side of a positive displacement pump before the discharge stop valve to prevent damage from excess pressure.
Step-by-step explanation:
When using a positive displacement pump, a pressure relief device must be located on the discharge side of the pump before the discharge stop valve. This is to ensure that any excess pressure from the pump can be relieved to prevent damage to the pump or to the system it is connected to.
Installing the relief device before the stop valve guarantees that it is always in the flow path regardless of whether the valve is open or closed, ensuring that the system is protected from overpressure at all times.