NIST APAR24 – Cooling/mixed air damper control is overlapping (Mode 5 – Unknown Occupied Mode)

Applicable Systems

  • NISTAPAR: APAR24
  • Primary: AHU, RTU, MUA, ERV

Objective/Method/Outcome

  • Objective: Indicates that the CCV is open while the MAD is modulating during occupied hours.
  • Method: Check if the CCV is open while the MAD is modulating for over 8 occupied hours per week while the unit is in Mode 5.
  • Outcome: An insight is generated when the CCV is open while the MAD is modulating for over 8 occupied hours per week while the unit is in Mode 5.

Logic

If( MAD > 20% Modulating; Temperature Threshold && CCV > 2% Open ) { return true; }
NIST APAR24 – Cooling/mixed air damper control is overlapping (Mode 5 – Unknown Occupied Mode)

Inputs

  • CCV {cmd, cool, water, valve} (Real Trend Log)
  • AHU_MODE_CTL {ahu, mode} (Real Trend Log)
  • MAD {cmd, mixed, air, damper} (Real Trend Log)

Parameters

Parameter Expression Block Series Number Description Default Value (Units)
Const – MAD min 81 The minimum damper position to be considered open 20 (%)
CCV Error Threshold 70 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. 0 (%)
Const – Damper signal threshold 82 The movement tolerance of the MAD. 2 (%)
Acceptable Hours per Week 73 The amount of time that this error is allowable for the unit per week. Anything more than that time is considered a fault. 8 (h)