Orion System VCM-X/RNE Operator Interfaces - Manual (Page 43)

VCM-X / RNE Operator Interfaces Technical Guide
VCM-X / RNE SETPOINTS
43
Setpoint Screen #19 - Outdoor Air CFM Control
VCM-X / RNE Spts
OA CFM CONTROL
Min CFM.: 0.10 K
Max CFM.: 0.10 K
If controlling the Outdoor Air Damper to a CFM setpoint, this screen
allows you to set the design Minimum and Maximum required Outdoor
Airfl ow CFM values for the Air Handler. The OA Max CFM limits the
damper operation during CO
2
override conditions. K = 1000
Description Minimum Default Maximum
OA Minimum CFM 0.10 K .10 K 200 K
OA Maximum CFM 0.10 K .10 K 200 K
Setpoint Screen #20 - Outdoor Air CFM
Deadband
VCM-X / RNE Spts
OA CFM CONTROL
OA CFM DB...: 10CFM
The is the deadband above and below the OA CFM Control Setpoint
which helps prevent hunting.
Description Minimum Default Maximum
OA CFM Deadband 0 CFM 10 CFM 20,000 CFM
Setpoint Screen #21 - Economizer Maximum
Position if High CO
2
Level
VCM-X / RNE Spts
Maximum Economizer
Position if High CO2
Level Occurs.: 100%
This Setpoint allows you to set the Maximum Position the Economizer
will open if high CO
2
conditions occur in the space. The Maximum
Economizer Position Setpoint is used to limit the amount of Outdoor Air
that will be introduced to the HVAC unit in order to ensure the unit is
operating within its Heating and Cooling design limitations. As shown
in the table below, the Minimum setting for this Setpoint is the value
previously set for the Economizer Min Position Setpoint.
Description Minimum Default Maximum
Maximum Economizer
Position If High CO
2
Level Occurs
Economizer
Minimum
Position
100% 100%
VCM-X / RNE Setpoint Screens
Setpoint Screen #17 - Economizer OAT/WB
Enable
VCM-X / RNE Spts
Economizer Setpoints
OAT/WB Enable: 55ºF
If an Outdoor Air Humidity Sensor is not connected to the VCM-X or
RNE and the Outdoor Air Temperature falls below this Setpoint, the
Economizer can be used for Free Cooling. If an Outdoor Air Humidity
Sensor is connected to the VCM-X or RNE, then a Wetbulb Temperature
will be calculated and used instead of the Outdoor Air Drybulb Tem-
perature to determine when Free Cooling can be used.
Description Minimum Default Maximum
Economizer Setpoints
OAT/WB Enable
0ºF 55ºF 80ºF
Setpoint Screen #18 - Economizer Minimum
Position & Control Rate
VCM-X / RNE Spts
Economizer Setpoints
Min Position.: 10 %
Control Rate.: 90
The Economizer (OA Damper) Min Position Setpoint is maintained
during the Occupied Mode even if the Economizer is disabled due to the
OA Temperature or Wetbulb Temperature being above the Economizer
Enable Setpoint. The Control Rate Setpoint allows you to adjust the
Economizer to modulate the OA Damper Actuator faster or slower as
desired. The Control Rate Setpoint range is 10-99. Larger numbers make
the Economizer Outdoor Air Damper Actuator modulate faster, smaller
numbers make the Outdoor Air Damper Actuator modulate slower.
Description Minimum Default Maximum
Economizer Min Position 0% 10% 100%
Economizer Control Rate 10 90 99
Revised: 9/14/12