Which parameter would be considered close to exceeding critical levels in this DX system?

In a direct expansion (DX) system, monitoring parameters such as pressures and temperatures is crucial for optimal operation and preventing damage. The compressor discharge temperature serves as a key indicator of the system's health and efficiency. A compressor discharge temperature of 265°F is alarmingly high; typically, discharge temperatures above about 230°F can indicate that the system is operating under excessive load or is experiencing issues, possibly leading to compressor failure if sustained.

As temperatures rise beyond recommended levels, the risk of overheating puts significant strain on the compressor and can lead to catastrophic failures. Thus, the value of 265°F is indicative of the system heading towards critical levels, necessitating immediate attention and corrective measures. In contrast, the other parameters mentioned are not approaching critical thresholds that would cause immediate concern for system integrity.