There are three factors which increase an air cooler’s inlet temperature:
• The compressor valves are faulty.
• The compression ratio has increased.
• High pressure, high temperature natural gas is being produced from the wellhead.
heat transfer surface area) a 10°F increase in compressor discharge temperature may increase the air cooler outlet temperature by 5-8°F. “Troubleshooting Reciprocating Compressors.” Temperature rises above those obtained from this correlation indicate bad compressor valves (plates or springs broken) or, less commonly, leakage across the piston rings in a double-acting cylinder.
Depending on the compression ratio, a 10°F increase in the compressor inlet pressure will translate into a considerably larger increase in compressor discharge temperature. Thus, it is conceivable that the cooler outlet temperature may increase due to the effect of putting high temperature wells on line.