What is the purpose of an oil trap installed in the discharge line on a vertical riser?

The purpose of an oil trap installed in the discharge line on a vertical riser is to prevent oil from draining back to the compressor. In HVAC systems, especially those using a refrigerant that can mix with oil, an oil trap helps keep the oil within the designated areas of the system, ensuring proper lubrication when needed. If oil were to drain back to the compressor, it could lead to insufficient lubrication in other parts of the system, potentially causing damage or inefficient operation.

The oil trap acts as a barrier that captures oil traveling through the discharge line, allowing refrigerant gases to pass while retaining oil in place. This is crucial for maintaining optimal compressor function and overall system performance. Proper oil management is necessary to prevent issues such as flooding in the compressor or other components, which can ultimately lead to system failure or inefficiency.