It is back to school for Johnny Tundra, who returns to Rosebud County Vo-Tech. A chiller keeps tripping offline on high head pressure. How can the chiller have any load on it when the temperature outside is 15°F? Lead designer Jerry Seltzer is ready to replace the chiller, fire the mechanical contractor, and sue the controller provider. Fortunately for everyone involved, Johnny has an advanced degree in troubleshooting.