Orion System SA Controller - Manual (Page 30)

Zone
Zone
Programming
SA Controller Operator Interface 30
Setpoint Screen #19 - Static Setpoint,
Deadband & Control Rate
SA Unit Spts ID 102
Static Spt...: 0.50”
Deadband.....: 0.10”
Control Rate.: 10 s
For VAV units, a Supply Fan VFD or Bypass Damper Actuator is used to
maintain the Duct Static Pressure Setpoint. The Static Pressure Output
Signal varies to control the Static Pressure Setpoint. If the Duct Static
Pressure is above the Static Setpoint plus the Deadband, the Static Pres-
sure Output Signal will be reduced at every Control Rate interval. If the
Static Pressure is below the Static Setpoint minus the Deadband, the
Output signal will be increased at every Control Rate interval.
The Duct Static Pressure Control Output Signal is a non-confi gurable
Direct Acting Signal (0-10 VDC). This can be used to directly connect
to a Supply Fan VFD without any modifi cations.
When you are using a Bypass Damper Actuator to control the Duct
Static Pressure, you must set up the Bypass Damper Actuator or the
Bypass Damper so that it is Reverse Acting in operation. The Output
Signal increases (closes Bypass Damper) if the Duct Static Pressure is
below the Duct Static Pressure Setpoint by the Deadband amount and
the Output Signal decreases (opens Bypass Damper) if the Static Pres-
sure is above the Setpoint by the Deadband amount.
Description Minimum Default Maximum
Static Spt 0.10″ WG 0.50″ WG 3.0″ WG
Deadband 0.10″ WG 0.10″ WG 1.0″ WG
Control Rate 1 Sec 10 Sec 30 Sec
SA Controller Setpoint Screens
Setpoint Screen #17 - Head Pressure Output
Minimum Position Setpoint
SA Unit Spts ID 102
Head Pressure
Output Min Position
Setpoint: 35%
This is the minimum position the Condenser Water Valve or the Con-
denser Fan will be allowed to modulate down to when the compressors
are active. This will ensure adequate water fl ow or airfl ow during
compressor cooling operation. For a Water Cooled Condenser, a proper
setting will prevent the Water Flow Switch from opening which would
create a proof of water fl ow Failure.
Description Minimum Default Maximum
Head Pressure Output
Minimum Position Setpoint
0% 35% 100%
Setpoint Screen #18 - Water Side Economizer
Setpoints
SA Unit Spts ID 102
Water Side Econo
Delta Spt: 10ºF
Deadband: 2ºF
If an Entering Air Humidity Sensor is not connected to the SA Control-
ler and the Entering Air Temperature falls below the Delta Setpoint, the
Economizer can be used for Free Cooling. If an Entering Air Humidity
Sensor is connected to the SA Controller, then a Wetbulb Temperature
will be calculated and used instead of the Entering Air Drybulb Tem-
perature to determine when Free Cooling can be used.
Description Minimum Default Maximum
WS Econo Delta Setpoint 3ºF 10ºF 20ºF
WS Econo Deadband 2ºF 2ºF 10ºF