Table 3.

Labeling basis on six types of classification.

Category	Description	Criteria
Normal condition	Standard operating conditions without any faults	All parameters within expected range; no anomalies or irregular patterns
Supply fan fault	Issues related to the HVAC system's fan	Significant deviations in airflow rate, fan speed, or electrical consumption patterns
Total heating pump fault	Issues related to the heating pump	Lower median and higher variance in heating pump status
Return air temperature sensor fault	Malfunctions in the sensors measuring return air temperature	Return temperature readings outside the 25th to 75th percentile range (13.55 °C to 20.2 °C)
Supply air temperature sensor fault	Malfunctions in the sensors measuring supply air temperature	Supply air temperature readings outside the 25th to 75th percentile range (18.21 °C to 27.44 °C)
Valve position fault	Problems with the heating valve operation	Failure to open/close as commanded, delays in response, abnormal range of motion, irregular position readings