74
damper position will never exceed the bounds specified by
IAQ.M and EC.MN during IAQ control.
If the building is occupied and the indoor fan is running and
the differential between IAQ and OAQ is less than DAQ.L, the
economizer will remain at IAQ.M. The economizer will not
close completely. The damper position will be 0 when the fan
is not running or the building is unoccupied. The damper posi-
tion may exceed EC.MN in order to provide free cooling.
The ComfortLink™ controls are configured for air quality
sensors which provide 4 mA at 0 ppm and 20 mA at 2000 ppm.
If a sensor has a different range, these bounds must be
reconfigured. These pertinent configurations for ranging the air
quality sensors are IQ.R.L, IQ.R.H, OQ.R.L and OQ.R.H. The
bounds represent the PPM corresponding to 4 mA (low) and
20 mA (high) for IAQ and OAQ, respectively.
If OAQ exceeds the OAQ Lockout Value (OAQ.L), then the
economizer will remain at IAQ.M. This is used to limit the use
of outside air which outdoor air CO2 levels are above the
OAQ.L limit. Normally a linear control of the damper vs. the
IAQ control signal can be used, but the control also supports
non-linear control. Different curves can be used based on the
Diff.IAQ Responsiveness Variable (IAQ.R). See Fig. 12.
SETTING UP THE SYSTEM — The IAQ configuration op-
tions are under the Local Display Mode Configuration
→
IAQ.
See Table 59.
IAQ Analog Sensor Config (Configuration
→
IAQ
→
AQ.CF
→
IQ.A.C) — This is used to configure the type of
IAQ position control. It has the following options:
•IQ.A.C = 0 (No analog input). If there is no other mini-
mum position control, the economizer minimum position
will be Configuration
→
IAQ
→
EC.MN and there will be
no IAQ control.
•IQ.A.C = 1 (IAQ analog input). An indoor air (space or
return air) CO2 sensor is installed. If an outdoor air CO2
sensor is also installed, or OAQ is broadcast on the CCN,
or if a default OAQ value is used, then the unit can per-
form IAQ control.
•IQ.A.C = 2 (IAQ analog input with minimum position
override) — If the differential between IAQ and OAQ
is above Configuration
→
IAQ
��
AQ.SP
→
DAQ.H, the
economizer minimum position will be the IAQ override
position (Configuration
→
IAQ
→
AQ.SP
→
IQ.O.P).
•IQ.A.C = 3 (4 to 20 mA minimum position) — With a 4
to 20 mA signal connected to TB202 terminal 11 and 12,
the economizer minimum position will be scaled linearly
from 0% (4 mA) to EC.MN (20 mA).
•IQ.A.C = 4 (10K potentiometer minimum position) — With
a 10K linear potentiometer connected to TB202 terminal 11
and 12, the economizer minimum position will be scaled
linearly from 0% (0 kilo-ohms) to EC.MN (10 kilo-ohms).
IAQ Analog Fan Config (Configuration
→
IAQ
→
AQ.CF
→
IQ.A.F) — This configuration is used to configure the control
of the indoor fan. If this option is used then the IAQ sensor
must be in the space and not in the return duct. It has the fol-
lowing configurations:
•IQ.A.F = 0 (No Fan Start) — IAQ demand will never
override normal indoor fan operation during occupied or
unoccupied period and turn it on.
•IQ.A.F = 1 (Fan On If Occupied) — IAQ demand will
override normal indoor fan operation and turn it on (if
off) only during the occupied period (CV operation with
automatic fan).
•IQ.A.F = 2 (Fan On Occupied/Unoccupied) — IAQ
demand will always override normal indoor fan operation
and turn it on (if off) during both the occupied and unoccu-
pied period. For IQ.A.F = 1 or 2, the fan will be turned on as
described above when DAQ is above the DAQ Fan On Set
Point (Configuration
→
IAQ
→
AQ.SP
→
D.F.ON). The fan
will be turned off when DAQ is below the DAQ Fan Off Set
Point (Configuration
→
IAQ
→
AQ.SP
→
D.F.OF). The con-
trol can also be set up to respond to a discrete IAQ input.
The discrete input is connected to TB204 terminal 11 and
12.
Table 59 — Indoor Air Quality Configuration
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
DCV.C DCV ECONOMIZER SETPOINTS
EC.MN Economizer Min.Position 0 - 100 % ECONOMIN 5
IAQ.M IAQ Demand Vent Min.Pos. 0 - 100 % IAQMINP 0
O.C.MX Economizer Min.Flow 0 - 20000 CFM OACFMMAX 2000
O.C.MN IAQ Demand Vent Min.Flow 0 - 20000 CFM OACFMMIN 0
O.C.DB Econ.Min.Flow Deadband 200 - 1000 CFM OACFM_DB 400
AQ.CF AIR QUALITY CONFIGS
IQ.A.C IAQ Analog Sensor Config 0 - 4 IAQANCFG 0
IQ.A.F IAQ 4-20 ma Fan Config 0 - 2 IAQANFAN 0
IQ.I.C IAQ Discrete Input Config 0 - 2 IAQINCFG 0
IQ.I.F IAQ Disc.In. Fan Config 0 - 2 IAQINFAN 0
OQ.A.C OAQ 4-20ma Sensor Config 0 - 2 OAQANCFG 0
AQ.SP AIR QUALITY SETPOINTS
IQ.O.P IAQ Econo Override Pos. 0 - 100 % IAQOVPOS 100
IQ.O.C IAQ Override Flow 0 - 31000 CFM IAQOVCFM 10000
DAQ.L Diff.Air Quality LoLimit 0 - 1000 DAQ_LOW 100
DAQ.H Diff. Air Quality HiLimit 100 - 2000 DAQ_HIGH 700
D.F.OF DAQ PPM Fan Off Setpoint 0 - 2000 DAQFNOFF 200
D.F.ON DAQ PPM Fan On Setpoint 0 - 2000 DAQFNON 400
IAQ.R Diff. AQ Responsiveness -5 - 5 IAQREACT 0
OAQ.L OAQ Lockout Value 0 - 2000 OAQLOCK 0
OAQ.U User Determined OAQ 0 - 5000 OAQ_USER 400
AQ.S.R AIR QUALITY SENSOR RANGE
IQ.R.L IAQ Low Reference 0 - 5000 IAQREFL 0
IQ.R.H IAQ High Reference 0 - 5000 IAQREFH 2000
OQ.R.L OAQ Low Reference 0 - 5000 OAQREFL 0
OQ.R.H OAQ High Reference 0 - 5000 OAQREFH 2000
IAQ.P IAQ PRE-OCCUPIED PURGE
IQ.PG IAQ Purge Yes/No IAQPURGE No
IQ.P.T IAQ Purge Duration 5 - 60 min IAQPTIME 15
IQ.P.L IAQ Purge LoTemp Min Pos 0 - 100 % IAQPLTMP 10
IQ.P.H IAQ Purge HiTemp Min Pos 0 - 100 % IAQPHTMP 35
IQ.L.O IAQ Purge OAT Lockout 35 - 70 dF IAQPNTLO 50