The dispatcher calls Bob and gives him a service call at a residence. The house is getting hot because the unit is not cooling even though it has been running. It is a 4-ton system.
The weather is really hot when Bob arrives, 96 degrees F. He pulls his truck to the back of the driveway to prevent blocking the homeowners' cars. Bob is familiar with the system. He goes to the front door and the wife comes to the door. She invites him in to check out the system. It is hot in the house. The thermostat's thermometer registers 84 degrees F. She tells Bob that the system had been working until it got really hot. He could hear the indoor fan running, but the air coming out of the registers is room temperature, not cold.