Applicable Systems
- Primary: MAT
Objective/Method/Outcome
- Objective: Determines whether the mixed air damper is leaking. The MAT should have a similar value OAT while drawing 100% outdoor air.
- Method: Compares the OAT and MAT while the unit is on and the MAD is fully open.
- Outcome: An insight is generated if weekly hours of irregularity exceeds weekly allowed hours.
Logic
- Input normalized mixed and outdoor air temperature statistics with the respected mixed air damper throughput percentage.
- If mixed air temperature exceeds outside air temperature, damper throughput is over 95% and the building is active; Calculate hours of irregularity.
- Aggregate daily hours to calculate the daily score.
- Aggregate daily score to calculate the weekly score.
- If the weekly score exceeds the outside air temperature threshold, generate an insight.
while( MAT > OAT AND MAD > 95% AND Occ = 1 ){
Calculate Hours of irregularity
Aggregate Daily Score
Aggregate Weekly Score
if( Weekly Score > OAT Threshold ){
Insight Trigger - MAT Outside of Range of OAT
}
}
Description / Method
Determines whether the mixed air damper is leaking. The MAT should have a similar value OAT while drawing 100% outdoor air.
Compares the OAT and MAT while the unit is on and the MAD is fully open.
Diagnosis / Recommended Action
- Mixed air damper stuck and/or leaking. Verify damper/actuator operation.
- Input sensor(s) faulty or miscalibrated. Verify input sensor(s) operation.
Message
The MAT is not within ±2 degrees of the RAT when the MAD is fully open to the outside air for more than 6 hours per week during occupied hours.
This implies that the MAD is leaking or stuck and drawing return air.
Notes
Based off of NIST APAR 10.CTL Generated:
- Weekly Air Damper Control Performance Score
Default Priority
Low
Inputs
| Inputs | Units | Default Value | Tags | Description |
|---|---|---|---|---|
| Mixed Air Damper | % | cmd, mixed, air, damper | Mixed air damper throughput percentage | |
| Mixed Air Temperature | °C/°F | sensor, mixed, air, temp | Mixed air temperature statistics | |
| Outdoor Air Temperature | °C/°F | sensor, outside, air, temp | Outdoor air temperature statistics | |
| Occupancy | occupied | Building operation status |
