Question 20Refrigeration & AC - Assistant Engineer

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.