Highlights

HVAC Mode Dependencies

The HVAC Mode settings in the AirflowSetpointControl folder affects a lot of factors in the VAV application. The below tables offers a basic summary.

HVAC Mode	Effective setpoint	Space temp. control loop	DAT control loop	Airflow setpoint	Fan control	Reheater control	Perimeter control
Auto	Heating demand active: effective setpoint equals the heating setpoint Cooling demand active: effective setpoint equals the cooling setpoint	Cooling CL active	Heating CL active: DAT > HotAirTempSetpoint the above temp. is maintained > ChangeoverDelay Cooling CL active: DAT < HotAirTempSetpoint the above temp. is maintained > ChangeoverDelay	Occupied and bypass: heating: linear function between the MaxOccHeatAirFlowSetpoint and MinOccHeatAirFlowSetpoint cooling: linear function between theMaxOccCoolAirFlowSetpoint and MinOccCoolAirFlowSetpoint Standby (StandbyAirFlowSetpoint) and unoccupied (UnoccAirFlowSetpoint): the same setpoint for heating and cooling	Parallel fan: working on heating demand Series fan: working if occupied or standby (if allowed)	According to the heating demand	According to the heating demand
Heat	Occupied: OccHeatTempSetpoint Bypass: OccHeatTempSetpoint Standby: StandbyHeatTempSetpoint Unoccupied: UnoccHeatTempSetpoint	Heating CL active	Heating CL active	Occupied and bypass: linear function between the MaxOccHeatAirFlowSetpoint and MinOccHeatAirFlowSetpoint values Standby (StandbyAirFlowSetpoint): setpoint the same as the auto mode Unoccupied (UnoccAirFlowSetpoint) and	Parallel fan: working on heating demand Series fan: working only on heating demand if occupied or standby (if allowed)	According to the heating demand	According to the heating demand
Cool	Occupied: OccCoolTempSetpoint Bypass: OccCoolTempSetpoint Standby: StandbyCoolTempSetpoint Unoccupied: UnoccCoolTempSetpoint	Cooling CL active	Cooling CL active	Occupied and bypass: linear function between the MaxOccCoolAirFlowSetpoint and MinOccCoolAirFlowSetpoint values Standby (StandbyAirFlowSetpoint): setpoint the same as the auto mode Unoccupied (UnoccAirFlowSetpoint): setpoint the same as the auto mode	Parallel fan: inactive Series fan: working only on cooling demand if occupied or standby (if allowed)	Off	Off
MorningWarmUp	Occupied: OccHeatTempSetpoint Bypass: OccHeatTempSetpoint Standby: StandbyHeatTempSetpoint Unoccupied: UnoccHeatTempSetpoint	Heating CL active	Heating CL active	MaxOccHeatAirFlowSetpoint	Parallel fan: if the WarmUpParallelFan variable is set to true, the parallel fan is active in this mode Series fan: ventilator set to the maximum speed	According to the heating demand (if WarmUpHeater is true)	According to the heating demand (if WarmUpHeater is true)
PreCool	Occupied: OccCoolTempSetpoint Bypass: OccCoolTempSetpoint Standby: StandbyCoolTempSetpoint Unoccupied: UnoccCoolTempSetpoint	Cooling CL active	Cooling CL active	MaxOccCoolAirFlowSetpoint	Parallel fan: inactive Series fan: ventilator set to the maximum speed	Off	Off
Night Purge	Occupied: OccCoolTempSetpoint Bypass: OccCoolTempSetpoint Standby: StandbyCoolTempSetpoint Unoccupied: UnoccCoolTempSetpoint	Cooling CL active	Cooling CL active	MaxOccCoolAirFlowSetpoint	Parallel fan: inactive Series fan: ventilator set to the maximum speed	Off	Off
Fire	Occupied: OccCoolTempSetpoint Bypass: OccCoolTempSetpoint Standby: StandbyCoolTempSetpoint Unoccupied: UnoccCoolTempSetpoint	Disabled	Disabled	MaxOccCoolAirFlowSetpoint	Disabled	Off	Off
Off	Occupied: OccCoolTempSetpoint Bypass: OccCoolTempSetpoint Standby: StandbyCoolTempSetpoint Unoccupied: UnoccCoolTempSetpoint	Disabled	Disabled	0	Off	Off	Off