Question 44Refrigeration/AC - QMED70% to pass
The coil temperature measured at the expansion valve sensing bulb of an operating system is 10°F. The low side pressure with the compressor running as shown on the gauge illustrated indicates 15 psig. What adjustments or changes, if any, should be made to the system? Illustration GS-RA-16
AI Explanation
The correct answer is B. The expansion valve should not be adjusted, as the degree of superheat is within the accepted range.
The coil temperature of 10°F and the low side pressure of 15 psig indicate that the system is operating within the normal range of superheat, which is typically between 6-12°F. Adjusting the expansion valve is not necessary in this case, as the system is functioning properly and the degree of superheat is appropriate.
The other answer choices are incorrect because: A) a fouled liquid line strainer would not cause the low side pressure and superheat to be within the normal range; C) changing the filter drier would not directly affect the superheat; and D) cleaning the evaporator coils is not necessary if the superheat is within the acceptable range.
Related Questions
#42 A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? #43 If the superheat setting of a thermostatic expansion valve is set too low, what would be the result, assuming that the system has a single evaporator? #45 If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? #46 If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? Illustration GS-RA-07 #47 What is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system?