Objective/Method/Outcome
Objective: Determines if the OAT and MAT are similar when outdoor air is open
Method: Compares the OAT and MAT to determine if they are inconsistent. Checks the recorded Supply Fan Status and OAD position to determine if the fan is running and the damper 100% open. If the damper is open but there is difference in temperature, the hours of fault is determined.
Outcome: Triggers an insight.
Description
Indicates an inconsistency between outdoor and mixed air temperatures while the OA damper is 100% open.
This rule is part of the CopperTree Standard rule-set, and is derived from NIST APAR10.
Default Priority
Low
Diagnosis
- Input sensor(s) faulty or miscalibration. Verify input sensor(s) operation.
- Mixed air dampers stuck, leaking, or not following control signal.
Message
Outdoor and mixed air temperatures vary while outdoor air damper is fully open.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| OAT | Outdoor Air Temperature | The recorded OAT | |
| MAT | Mixed Air Temperature | The recorded MAT | |
| OAD | Outdoor Air Damper Position, Outdoor Air Damper Command | The recorded Outdoor Air Damper Position | |
| SF Status | Discharge Air Fan Command, Discharge Air Fan Status | The recorded Supply Fan Status | |
| Threshold – Temperature Difference | The minimum difference in temperature that can trigger an insight | ||
| Threshold – Weekly Hours of Faulty Operation | The minimum hours of faulty operation per week that can trigger an insight |
Notes
Default Thresholds:
- Temperature Threshold: 2°
- Weekly Hours of Variance: 8
