An accumulator is used to

• A. store high-pressure gas
• B. Prevent liquid refrigerant from reaching the compressor
• C. separate oil from refrigerant
• D. filter moisture

Answer: (D)

The main idea is protecting the compressor by keeping liquid refrigerant out of the suction side. An accumulator sits on the suction line after the evaporator and acts as a liquid trap, capturing any liquid that might be carried over with the vapor. By allowing only vapor to flow back to the compressor, it prevents liquid slugging, which can damage the compressor and disrupt lubrication. Over time, the liquid in the accumulator tends to vaporize and be drawn into the compressor as needed, further reducing the risk of liquid impact.

This isn’t the device that stores high-pressure gas, which would be on the high-pressure side of the system. It isn’t primarily used to separate oil from refrigerant—that role belongs to an oil separator. And it isn’t meant to filter moisture—that function is carried out by the filter-drier. So the accumulator’s key purpose is to prevent liquid refrigerant from reaching the compressor.