What devices must control pressure between a nitrogen cylinder and the connected refrigeration circuit?
- A suitable regulator and rated test setup
- BA household air hose for the described HVAC equipment and measured operating conditions
- CAn oxygen regulator
- DNo pressure control
Why A is correct
The best answer is: A suitable regulator and rated test setup. Cylinder pressure can exceed system and gauge ratings. A compatible regulator, relief and rated hoses or manifold provide controlled test pressure. The transferred operating condition requires the same design, installation, diagnostic, or safety principle in a different HVAC context. The other choices skip a prerequisite, conflict with the listed procedure, or treat a symptom without controlling its cause.