A split air conditioning system has two valves located in the outdoor unit or condenser. The refrigerant gas is pre-charged from the factory in the condenser unit. When these valves are opened and the pipes are connected to the indoor unit, the gas flows throughout the system.
Key points to understand:
- The thicker valve is connected to the pipe that receives gas from the evaporator, a low-pressure point.
- The thinner valve is connected to the pipe located right after the capillary tube, also a low-pressure point, but in the liquid line before the evaporator.
Which Valve Should Be Opened First?
Before turning the system on for the first time, it’s recommended to open the thinner valve first (liquid line).
Why Open the Thinner Valve First?
- Opening the thinner valve allows the refrigerant to flow in a controlled manner through the capillary tube and into the evaporator.
- If the thicker valve (vapor line) is opened first, the refrigerant may suddenly drag part of the compressor’s lubricant oil into the evaporator. This happens because the gas flow through the thicker valve is not regulated by the capillary tube.
Recommended Procedure
- Slowly open the thinner valve (liquid line). This minimizes the risk of losing compressor oil.
- Once the refrigerant has properly circulated through the system, carefully open the thicker valve (vapor line).
Important Considerations
- While it’s unlikely that a small loss of oil will cause immediate damage to the compressor, any lost oil will take a long path before returning to the compressor.
- Oil loss during the initial setup can have long-term effects on the compressor’s performance and lifespan.
Conclusion
To ensure proper functioning and prolong the system’s life, always open the thinner liquid line valve first. This practice ensures controlled refrigerant flow and minimizes the risk of oil loss from the compressor.
