Question 125Refrigeration & AC - QMED

The correct answer is D) discharge of the compressor lube oil pump. The fluid used as the source of actuating power against the underside of the unloader power element piston of the refrigeration compressor capacity control mechanism is obtained from the discharge of the compressor lube oil pump. This is because the lube oil pump is designed to provide pressurized oil to the various components of the compressor, including the capacity control mechanism, to ensure proper lubrication and operation. The other options are incorrect because A) a secondary hydraulic pump is not typically used for this purpose, B) the high side liquid receiver does not contain the necessary pressurized fluid, and C) the gas discharge from the compressor would not provide the required actuating power.