Which gas must never be used to pressurize or leak test a refrigeration system?

Which gas must never be used to pressurize or leak test a refrigeration system?

• A. Oxygen
• B. Nitrogen
• C. Helium
• D. CO2

Answer: (A)

Safety during pressurizing and leak testing a refrigeration system relies on using a gas that won’t feed a fire or react with oils and refrigerants. Oxygen must never be used because it supports combustion. If there’s a leak, an oxygen-rich environment can cause even a small spark or hot surface to ignite flammable refrigerants or lubricants, turning a minor issue into a dangerous fire. That’s why inert, non-flammable gases such as nitrogen or helium are preferred for these tests. Carbon dioxide is sometimes used, but it introduces asphyxiation risks as well. In short, oxygen is avoided to prevent fires and explosions during leak testing.

Safety during pressurizing and leak testing a refrigeration system relies on using a gas that won’t feed a fire or react with oils and refrigerants. Oxygen must never be used because it supports combustion. If there’s a leak, an oxygen-rich environment can cause even a small spark or hot surface to ignite flammable refrigerants or lubricants, turning a minor issue into a dangerous fire. That’s why inert, non-flammable gases such as nitrogen or helium are preferred for these tests. Carbon dioxide is sometimes used, but it introduces asphyxiation risks as well. In short, oxygen is avoided to prevent fires and explosions during leak testing.