Question 41Refrigeration/AC - QMED70% to pass
Which of the following statements describes the accepted method for testing a thermostatic expansion valve?
AI Explanation
The correct answer is D) Place the sensing bulb in ice water and then warm by hand. Observe flood-through and temperature change at the suction line.
This is the accepted method for testing a thermostatic expansion valve because it allows you to observe the valve's response to changes in temperature. By chilling the bulb in ice water and then warming it by hand, you can see the valve stem move and monitor the corresponding changes in suction pressure and temperature, which confirms the proper operation of the valve.
The other options are incorrect because they do not accurately test the valve's response to temperature changes. Option A would only show the compressor's reaction, not the valve's. Option B requires removing the power head, which is not the standard testing procedure. Option C uses a heat source that could potentially damage the valve.
Related Questions
#39 Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way? #40 Which of the illustrated gauges is capable of measuring vacuums at the micron level for the purpose of proving system dehydration during system evacuation with a vacuum pump, but displays the achieved vacuums at incremental threshold intervals rather than continuously? Illustration GS-RA-37 #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? #44 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