When using nitrogen to charge a system, what piece of equipment should it be charged through, and where should a relief valve be located?

1. Charge through a refrigeration manifold with a relief valve on the nitrogen cylinder.
2. Charge through a pressure regulator (make sure the nitrogen cylinder has a regulator on it) and insert a relief valve in the downstream line from the pressure regulator.
3. Install a relief valve prior to the pressure regulator.
4. None of the above.

Charge a system using nitrogen through a pressure regulator, ensuring both the cylinder and charging setup have regulators and placing a relief valve downstream from the pressure regulator for safety. So, the correct option is 1 Charge through a refrigeration manifold with a relief valve on the nitrogen cylinder.

Explanation:

When using nitrogen to charge a system, it is important to handle the gas safely by using the appropriate equipment. The correct method is to charge through a pressure regulator with the nitrogen cylinder also equipped with a regulator. Additionally, it is crucial to insert a relief valve downstream from the pressure regulator. This ensures that any excess pressure buildup can be safely released without causing harm or damage to the system or the operator. The presence of a relief valve on the nitrogen cylinder itself is a standard safety feature.