Carrier 48PG03-16 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 74

ECONOMIZER
MINIMUM
DAMPER
POSITION
(EC. MN)
MINIMUM
IAQ
DAMPER
POSITION
(AQ. MN)
IA.CF = 3 (Control Minimum Position)
When IA.CF = 3, an external 4 to 20 mA source is used to set the
minimum position. The 4 mA signal corresponds to 0% and the
20 mA signal corresponds to 100%. In this mode, configurations
such as Configuration→AIR.Q→EC.MN and Configuration→
AIR.Q→AQ.MN are not used.
If the indoor fan is not operating, the economizer position will be
zero. The damper position may exceed the economizer minimum
position to provide economizer cooling.
IAQ (Switch Input)
Indoor air quality can also be measured using a switch input. For
the purpose of specifying the type of switch input, low CO
levels are considered normal. The IAQ switch input is defined by
the configuration by Configuration →AIR.Q→II.CF IAQ Level
(Switch Input). Enthalpy and IAQ are controlled by the same
switch input and therefore they cannot be used simultaneously.
Configuration→AIR.Q→II.CF = 0 (No IAQ)
The II.CF = 0 configuration signifies that there is no IAQ switch
input. The damper will operate at the EC.MN position when the
space is occupied and the indoor fan is on.
Configuration→AIR.Q→II.CF = 1 (DCV NO) or II.CF = 2
(DCV NC)
The Demand Control Ventilation (DCV) allows the economizer
minimum position to be decreased when there is no IAQ
problem. If IAQ is low, the economizer minimum position is
Minimum IAQ Damper
→AIR.Q→AQ.MN). If IAQ is high, the economizer minimum
position is the Economizer Minimum Position (Configuration
→AIR.Q→EC.MN).
VENTILATION FOR PEOPLE
VENTILATION FOR SOURCES
100
AQ
DIFFERENTIAL
LOW (AQD.L)
Fig. 16 --- IAQ Control
2
Position (Configuration
700 INSIDE/OUTSIDE CO
AQ
DIFFERENTIAL
HIGH (AQD.H)
Configuration→AIR.Q→II.CF = 3 (Override NO) or
II.CF = 4 (Override NC)
The damper override function permits absolute positioning of the
economizer damper for ventilation purposes. The override is
active when IAQ is high and inactive when IAQ is low. The
override position is configurable by the configuration by
Configuration
→AIR.Q→OVR.P
Position).
Outdoor Air Quality (Analog Input)
The ComfortLink control is configured for outdoor air quality
sensors which provide 4 to 20 mA for 0 to 2000 ppm. If a sensor
has a different range, the ppm display range must be reconfigured
by entering new values for Configuration→AIR.Q →O.4M and
Configuration→AIR.Q→O.20M.
Configuration→AIR.Q→OA.CF = 0 (No OAQ)
This signifies there is no outdoor air sensor installed. The default
value of OAQ is 400 ppm.
Configuration→AIR.Q→OA.CF = 1 (DCV)
The outdoor air quality sensor analog input is for the value of
OAQ.
Configuration→AIR.Q→OA.CF = 2 (OAQ Lockout)
The outdoor air quality sensor analog input is only used to lock
out the outdoor ventilation. The economizer commanded position
is set to 0% when the ppm exceeds the OAQ lockout value
configured for Configuration→AIR.Q→OAQ.L. The default
value of OAQ.L is 600 ppm.
74
DIFFERENTIAL
2
C07010
(Economizer Override