Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 38

IAQ.L to OPEN means that when the switch is open, the input
will read LOW. When the switch is closed, the input will read
HIGH. Setting IAQ.L to CLSE (closed) means that when the
switch is closed, the input will read LOW, and therefore, when the
switch is open, the switch will read HIGH.
There are 2 possible configurations for the IAQ discrete input. Se-
lect item Configuration  IAQ  AQ.CF  IQ.I.C and configure
for either 1 (IAQ Discrete) or 2 (IAQ Discrete Override).
IQ.I.C = 1 (IAQ Discrete)
If the user sets IQ.I.C to 1 (IAQ Discrete), and the switch logic
(Configuration  IAQ  SW.LG  IAQ.L) is set to OPEN,
then an open switch reads LOW and a closed switch reads
HIGH.
If the switch is open, the economizer will be commanded to the
IAQ Demand Vent Minimum Position. If the outdoor flow sta-
tion is installed and outdoor air cfm can be read, the economiz-
er will move to the IAQ Demand Vent Minimum Flow CFM
control setting.
These settings may be adjusted and are located here:
Configuration  IAQ  DCV.C  IAQ.M
Configuration  IAQ  DCV.C  O.C.MN
If the switch is closed, the IAQ reading will be high and the
economizer will be commanded to the Economizer Minimum
Position. If the outdoor airflow station is installed and outdoor
air cfm can be read, the economizer will move to the Econo-
mizer Minimum Flow CFM control setting.
These settings may be adjusted and are located here:
Configuration  IAQ  DCV.C  EC.MN
Configuration  IAQ  DCV.C  O.C.MX
IQ.I.C = 2 (IAQ Discrete Override)
If the user sets IQ.I.C to 2 (IAQ Discrete Override), and Con-
figuration  IAQ  SW.LG  IAQ.L is set to OPEN, then an
open switch reads LOW and a closed switch reads HIGH.
If the switch reads LOW, no action will be taken. If the switch
reads HIGH, the economizer will immediately be commanded
to the IAQ Economizer Override Position. This can be set from
0 to 100% and can be found at Configuration 
IAQ  AQ.SP  IQ.O.P.
FAN CONTROL FOR THE IAQ DISCRETE INPUT
Under Configuration  IAQ  AQ.CF, the IQ.I.F (IAQ Dis-
crete Input Fan Configuration) must also be set. There are 3
configurations for IQ.I.F. Select the configuration that will be
used for fan operation. This configuration allows the user to
decide whether the IAQ discrete switch will start the fan (if the
supply fan is not already running), and in which state of occu-
pancy the fan will start.
IQ.I.F = 0 Minimum Position Override Switch input will
not start fan
IQ.I.F = 1 Minimum Position Override Switch input will
start fan in occupied mode only
IQ.I.F = 2 Minimum Position Override Switch input will
start fan in both occupied and unoccupied modes
IAQ ANALOG INPUT CONFIGURATION
This is an analog input located on the main base board (MBB).
There are 4 different functions for this input. The location of this
configuration is at Configuration  IAQ  AQ.CF  IQ.A.C.
The functions possible for IQ.A.C are:
• 0 = no IAQ analog input
• 1 = IAQ analog input
• 2 = IAQ analog input used to override to a set position
• 3 = 4 to 20 mA 0 to 100% economizer minimum position
control
• 4 = 0 to 10,000 ohms 0 to 100% economizer minimum posi-
tion control
Options 2, 3, and 4 are dedicated for third party control.
IQ.A.C = 2 (IAQ Analog Input Used to Override)
Under Configuration  IAQ  AQ.SP, set IQ.O.P (IAQ Econ-
omizer Override Position). The IQ.O.P configuration is adjust-
able from 0 to 100%. These configurations are also used in
conjunction with Configuration  IAQ  AQ.CF  IQ.A.F
(IAQ 4 to 20 mA Fan Configuration). There are 3 configura-
tions for IQ.A.F, and they follow the same logic as for the dis-
crete input. This configuration allows the user to decide (if the
supply fan is not already running) if the IAQ Analog Minimum
Position Override input will start the fan and in which state of
occupancy the fan will start.
.
IQ.A.F = 0 IAQ analog sensor input cannot start the sup-
ply fan
IQ.A.F = 1 IAQ analog sensor input can start the supply
fan in occupied mode only
IQ.A.F = 2 IAQ analog sensor input can start the supply
fan in both occupied and unoccupied modes
If IQ.A.F is configured to request the supply fan, then configu-
rations D.F.ON and D.F.OF need to be set. These configura-
tion settings are located under Configuration  IAQ  AQ.SP,
and configure the fan override operation based on the differen-
tial air quality (DAQ). If DAQ rises above D.F.ON, the control
will request the fan on until DAQ falls below D.F.OF.
NOTE: If D.F.ON is configured below DAQ.H, the unit is in
occupied mode, and the fan was off, then DAQ rose above
D.F.ON and the fan came on, the economizer will go to the
economizer minimum position (EC.MN).
The 4 to 20 mA signal from the sensor wired to TB201-8 and
TB201-7 is scaled to an equivalent indoor CO
rameters IQ.R.L and IQ.R.H located under the Configura-
tion  IAQ  AQ.SR menu. The parameters are defined such that
4 mA = IQ.R.L and 20 mA = IQ.R.H. When the differential air
quality DAQ (IAQ – OAQ.U) exceeds the DAQ.H set point (Con-
figuration  IAQ  AQ.SP menu) and the supply fan is on, the
economizer minimum
tion  IAQ  DCV.C  EC.MN) is overridden and the damper is
moved to the IQ.O.P configuration. When the DAQ falls below
the DAQ.L set point (Configuration  IAQ  AQ.SP menu), the
economizer damper is moved back to the minimum vent position
(EC.MN).
NOTE: Configuration OAQ.U is used in the calculation of the
trip point for override and can be found under Configura-
tion  IAQ  AQ.SP.
IQ.A.C = 3 (4 to 20 mA Damper Control)
This configuration will provide full 4 to 20 mA remotely con-
trolled analog input for economizer minimum damper position.
The 4 to 20 mA signal is connected to terminals TB201-8 and
TB201-7. The input is processed as 4 mA = 0% and 20 mA =
100%, thereby giving complete range control of the effective
minimum position.
The economizer sequences can be disabled by unplugging the
enthalpy switch input and not enabling any other economizer
changeover sequence at Configuration  ECON  E.SEL.
Complete control of the economizer damper position is then
possible by using a 4 to 20 mA economizer minimum position
control or a 0 to 10,000-ohm 0 to 100% economizer minimum
position control via configuration decisions at Configura-
tion  IAQ  AQ.CF  IQ.A.C.
To disable the standard enthalpy control input function, unplug
the enthalpy switch and provide a jumper from TB201-6 to
TB201-5 (see wiring diagrams in Major System Components
section on page 134).
IQ.A.C = 4 (10,000 ohm Potentiometer Damper Control)
This configuration will provide input for a 10,000-ohm linear
potentiometer that acts as a remotely controlled analog input for
economizer minimum damper position. The input is processed
38
(IAQ) by the pa-
2
vent position (Configura-