Question 188Refrigeration & AC - Assistant Engineer
70% to passAn air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15°F, but it is currently operating with a stable return air temperature of 0°F. The fresh air makeup vent is closed, the unit is operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating valve 100% open). Using the illustrated troubleshooting guide, what would be the normal range of expected discharge pressures if the ambient air temperature is 90°F? Illustration GS-RA-52
A150-190 psig
B160-180 psig
C190-230 psig
D200-220 psig
AI Explanation
The correct answer is A) 150-190 psig. Based on the given information about the refrigeration system (R-134a refrigerant, -15°F box temperature set point, 0°F return air temperature, 460 VAC/60 Hz, and 90°F ambient temperature), the normal range of expected discharge pressures would be 150-190 psig. This is the correct answer because the discharge pressure for an R-134a refrigeration system operating under these conditions typically falls within this range. The other answer choices are incorrect because B) 160-180 psig is too narrow of a range, C) 190-230 psig is too high, and D) 200-220 psig is also too high for the given system parameters.
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