Question 57Refrigeration & AC - Assistant Engineer

The correct answer is C) permit repacking the valve stem under pressure without shutting down. Refrigeration system isolation valves are designed with a backseat and a front seat to allow the valve stem to be repacked without shutting down the system. The backseat feature creates a seal that isolates the valve stem packing from the high-pressure refrigerant, enabling maintenance and repacking to be performed safely while the system is still in operation. The other answer choices are incorrect because they do not accurately describe the primary purpose of the backseat design. Option A is incorrect as the backseat does not allow the valve to function as a suction or discharge valve. Option B is incorrect as the backseat feature is not intended for valve removal and replacement. Option D is incorrect as the backseat does not enable the valve to operate as a liquid or vapor valve.