Compare R-407C and R-404A in terms of typical applications and operating temperatures.

Compare R-407C and R-404A in terms of typical applications and operating temperatures.

• A. R-407C is used in low-temperature display cases; R-404A as replacement for R-22.
• B. R-407C is used in air conditioning and mid-temperature; R-404A in low-temperature commercial applications.
• C. Both have identical pressure-temperature characteristics.
• D. R-407C is a blend of ammonia and refrigerant; R-404A is hydrocarbon.

Answer: (D)

R-407C and R-404A are designed for different temperature ranges, which is why they’re used in different types of equipment. R-407C is a mid-temperature blend used mainly in air conditioning and mid-temperature refrigeration. It’s chosen for systems like residential and light commercial AC and many mid-temp display cases because its pressure–temperature characteristics suit typical indoor cooling loads and coil temperatures. R-404A, on the other hand, is a low-temperature blend used in commercial refrigeration that requires very cold evaporation. It’s common in freezer cases, blast chillers, and other low-temp applications where the refrigerant must absorb heat at much lower temperatures. Neither refrigerant contains ammonia nor is either a hydrocarbon. R-407C is made from R-32, R-125, and R-134a, while R-404A is a blend of R-125, R-143a, and R-134a.

R-407C and R-404A are designed for different temperature ranges, which is why they’re used in different types of equipment. R-407C is a mid-temperature blend used mainly in air conditioning and mid-temperature refrigeration. It’s chosen for systems like residential and light commercial AC and many mid-temp display cases because its pressure–temperature characteristics suit typical indoor cooling loads and coil temperatures.

R-404A, on the other hand, is a low-temperature blend used in commercial refrigeration that requires very cold evaporation. It’s common in freezer cases, blast chillers, and other low-temp applications where the refrigerant must absorb heat at much lower temperatures.

Neither refrigerant contains ammonia nor is either a hydrocarbon. R-407C is made from R-32, R-125, and R-134a, while R-404A is a blend of R-125, R-143a, and R-134a.