The scan tool has the capability of displaying various HVAC information. This information assists in determining whether or not the HVAC control head is sending or receiving the proper data to various systems/components. The HVAC control head uses data received from other systems in order to carry out some functions. Therefore, if the HVAC control head receives the incorrect data from another system, the HVAC system may function improperly. Use the scan tool in order to review the data that interacts with the HVAC control head.

The scan tool can also display the status of the various HVAC inputs. Select the HVAC input status display in order to read the data and determine if the inputs can be properly interpreted. The display also indicates if the input has changed states. For example, when the outside temperature changes, the scan tool will display the change of the input status of the outside temperature sensor. Use this kind of information when diagnosing a malfunction associated with a particular HVAC input or an input that is shared with another system.

Use the scan tool to cycle the HVAC control head output functions. When the HVAC control head output cycling is selected, the scan tool can command the HVAC control head to cycle an output. This feature can be used to determine if the HVAC control head is able to cycle an output regardless of inputs or specific program instructions. Once a test is selected, the scan tool will command the HVAC control head to energize the selected output. The scan tool will then displays the status of the selected output. For example, a command can be sent to the LH electric actuator to move to the full hot or full cold position. After the command is sent, the LH electric actuator will send a position feedback signal to HVAC control head indicating its movement. The displayed information represents only what was commanded, not the action which actually took place.