NIST APAR13 – Cooling coil valve command is fully open and SAT error exists (Mode 3 – Mech. Cooling w/100% OA)
Applicable Systems
NISTAPAR: APAR13
Primary: AHU, RTU, MUA, ERV
Objective/Method/Outcome
Objective: Indicates that the cooling coil valve is fully open and the SAT is greater than the setpoint while the AHU is in Mode 3 (Mech. Cooling w/100% OA)
Method: Check if the SAT is more than 2 degrees above set point for over 8 occupied hours per week while the unit is in Mode 3
Outcome: An insight is generated when the SAT is more than 2 degrees above set point for over 8 occupied hours per week while the unit is in Mode 3
Logic
If (SAT - SAT SP > Temperature Threshold && CCV Open) { return true; }
NIST APAR13 – Cooling coil valve command is fully open and SAT error exists (Mode 3 – Mech. Cooling w/100% OA).
Inputs
SAT {sensor, discharge, air, temp} (Real Trend Log)
The movement tolerance of the CCV. This is used to define when the valve is open -everything above the formula (100 – CCV Error Threshold) is considered saturated.
2 (%)
Temperature Threshold
75
The acceptable temperature deviation from setpoint that is considered normal
2 (C)
Acceptable Hours per Week
60
The amount of time that this error is allowable for the unit per week. Anything more than that time is considered a fault.
