What can lead to a higher compressor ratio in air conditioning systems?

A higher compressor ratio in air conditioning systems typically occurs when there's a restriction or inefficiency in the system that causes it to work harder to achieve the desired cooling effect. A dirty condenser coil can significantly impact the system's performance. When the condenser coil is dirty, its ability to dissipate heat is compromised. This leads to elevated head pressure as the refrigerant cannot effectively release heat into the outdoor environment. As a result, the compressor must work harder to pump the refrigerant, leading to an increased compressor ratio.

In contrast, overcharging the system can lead to other issues, such as liquid refrigerant returning to the compressor, but it may not consistently result in a higher compressor ratio in the same way a dirty coil does. Large refrigerant lines can actually reduce pressure drops and improve efficiency when sized properly, while incorrect thermostat settings primarily affect the operational status rather than directly causing a change in compressor ratio. Thus, a dirty condenser coil is the most relevant factor in leading to a higher compressor ratio in air conditioning systems.