eZV-440 Version 2.1 Application Guide
Page 52 of 67
Document Edition 2.5
When the opening of windows is being monitored and an open window is detected, all heat and
cooling stages are disabled. Heating is re-enabled when the space temperature falls below
6 °C.
Discharge Air Temperature
The discharge air temperature (DAT) is the duct temperature downstream from any local
heating or cooling stages that supply the air to that space.
When the discharge air temperature approaches discharge air temperature high limit setpoint
(DATHiLimitSetpoint), the duct heating stages are disabled in sequence.
Damper and Airflow Control
The damper controls maintain an airflow setpoint that resets based on space heating or cooling
demand.
Airflow Setpoints
The following setpoints described in this section are accessible on the Setpoints tab on the
configuration page:
•
HeatingMaximum = maximum heating airflow setpoint
•
HeatingMinimum = minimum heating airflow setpoint
•
CoolingMinimum = minimum cooling airflow setpoint
•
AirflowDemand = Airflow demand in % (AV808)
At no time can CoolingMaximum be lower than CoolingMinimum or CoolingMinimum be greater
than CoolingMaximum but they can be the same.
HeatingMaximum can never be lower than HeatingMinimum and HeatingMinimum can never be
greater than HeatingMaximum. But HeatingMaximum and HeatingMinimum can be equal to
each other.
The following table shows the damper staging order and how airflow setpoint is calculated:
Space demand
Box Mode
Airflow Setpoint
Heating Demand
HeatCmd or AutoHeat (hot
air in the duct)
The damper is the first stage of heat.
As the Airflow Demand increases from 0 to 100%, the
airflow setpoint increases from the HeatingMinimum to the
HeatingMaximum setpoint.
