Question 20Refrigeration/AC - Assistant Engineer70% to pass
Which of the following conditions will occur if the power element of the thermostatic expansion valve shown in the illustration loses its charge? Illustration GS-RA-07
AI Explanation
The correct answer is D) The valve will fail closed, providing no cooling capacity.
When the power element of the thermostatic expansion valve loses its charge, the valve spring will cause the valve to close, shutting off the flow of refrigerant to the evaporator. This will result in a complete loss of cooling capacity, as the valve will fail in the closed position and prevent any refrigerant from reaching the evaporator.
The other options are incorrect because: A) the valve will not fail open, as it is designed to close without pressure in the power element; B) the external equalizing line cannot keep the valve unseated if the power element is uncharged; and C) the valve is not designed to fail open to provide continuous cooling when the power element is lost.
Related Questions
#18 A small obstruction at the thermostatic expansion valve inlet will result in which of the following conditions? #19 An obstructed expansion valve may be indicated by an incompletely cooled evaporator and what other symptom? #21 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 #22 If the superheat value of the thermostatic expansion valve is adjusted too high, what would be the result? #23 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?