48 ECY-303 Preloaded Applications
Temperature Management
Cooling Mode:
If the unit is equipped with an economizer, the mechanical cooling stages and the dampers are con-
trolled in sequence to maintain the space temperature at the effective cooling temperature setpoint
(ActCoolSP-AV36). The cooling stages are enabled only if OatCompEnable(BV22) is enabled. The
dampers are enabled only if EconEnable(BV23) is enabled.
When both OatCompEnable and EconEnable are enabled, the dampers are used as a first stage of
cooling before enabling the mechanical cooling stages. When cooling is required, the dampers are
controlled to maintain the discharge temperature at the Discharge air temperature setpoint Dampers-
DischAirSP(AV30).
When the system is equipped with a discharge air temperature sensor, the cooling stages are enabled
only when the discharge air temperature is above DischTempCoolSP(AV79). When the discharge air
temperature drops below DischTempCoolSP(AV79) – DischTempCoolDB(AV80), a cooling stage is
stopped. Delays can be configured for stage on CoolStgOnDelay(AV26) and stage off delay CoolSt-
gOffDelay(AV27).
Heating Mode:
If the unit is a heat pump unit (RevValveConfig-MSV23 = Cooling or Heating), the compressor stages
and the electric/gas heaters are controlled in sequence to maintain the space temperature at the effec-
tive heating temperature setpoint ActHeatSP(AV37). The compressor stages are enabled only if Oat-
CompEnable(BV22) is enabled. The electric/gas heaters are enabled only if OatHeatEnable(BV21) is
enabled. The proportional heating PropHeatConfig(MSV34) is controlled in sequence with the electric/
gas heating stages. The proportional heating is the first stage of heating.
When both OatCompEnable and OatHeatEnable are enabled, the compressor stages are used as a
first stage before enabling the electric/gas heater stages.
When the system is equipped with a discharge air temperature sensor, the heating stages are enabled
only when the discharge air temperature is below DischTempHeatSP(AV81). When the discharge air
temperature raise above DischTempHeatSP(AV81) + DischTempHeatDB(AV82), a heating stage is
stopped. Delays can be configured for stage on HeatStgOnDelay(AV28) and stage off delay HeatSt-
gOffDelay(AV29).
Fan Control
The fan is controlled based on the FanModeCmd(MSV3), FanStartDelay(AV34), FanStopDelay(AV35)
and InitStartdelay(AV85)
On a restart of the controller, InitStartDelay will prevent the fan from running for the first seconds. This
delay can be set to a different value in all of the controllers on a site to limit peak after a power failure/
restore.
When FanModeCmd is set to On, the fan will be set to On when the system is either in Occupied or
Bypass mode. When the system is in unoccupied or standby mode, the fan will start if there is a re-
quest to heat or cool the space.
When FanModeCmd is set to Auto, the fan will be set to On only if there is a request to heat or cool
the space.
The FanStartDelay and FanStopDelay will prevent the fan from short cycling.
Humidity Control
The humidifier can be configured using HumidifierConfig (MSV36), the humidifier can be 0-10V,
2-10V, PWM or digital. The humidifier will be controlled to maintain the return or space humidity to the
SpaceHumiditySP(AV53). If a discharge air humidity sensor is installed, the humidifier will be limited
when the discharge humidity is above DischHumiditySP(AV55).
Sequence of Operation
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