Outdoor Air Quality (Analog Input); Fan Enable (Analog Iaq Sensor); Fan Enable (Switch Input); Optional Humidi-Mizer Dehumidification System - Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting

the IAQ Switch Input Config (Configuration
Enthalpy and IAQ are controlled by the same switch input and
therefore cannot be used simultaneously.
II.CF = 0 (No IAQ)
The II.CF = 0 configuration signifies that there is no IAQ
switch input. The damper will operate at the Econ Min at Max
Fan Speed (Configuration
sponding damper position curve based on indoor fan speed
when the space is occupied and the indoor fan is on.
II.CF = 1 (DCV Normally Open) or II.CF = 2 (DCV Nor-
mally Closed)
The Demand Controlled Ventilation (DCV) allows the econo-
mizer minimum position to be decreased when there is no IAQ
problem. If IAQ is low, the economizer minimum position is
Econo Min IAQ Position (Configuration
when the indoor fan is operating at Supply Fan Maximum

Speed (Configuration UNIT
economizer minimum position is Econ Min at Max Fan Speed
 
(Configuration ECON
erating at Supply Fan Maximum Speed (FS.MX). If the fan
speed is modulating, see Fig. 8 for higher or lower damper po-
sition setting at the specific fan speed.
II.CF = 3 (Override Normally Open) or II.CF = 4 (Override
Normally Closed)
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 configured by the IAQ Override Position
 
(Configuration AIR.Q

OUTDOOR AIR QUALITY (ANALOG INPUT)

The ComfortLink control can be configured for outdoor air
quality sensors which provide a 4 to 20 mA signal correspond-
ing to 0 to 2000 ppm CO . If a field supplied sensor has a dif-
2
ferent range, the ppm display range must be reconfigured by
entering new values for the OAQ Sensor Value at 4mA (Con-
 
figuration AIR.Q O.4M) and OAQ Sensor Value at 20mA
 
(Configuration AIR.Q
OA.CF = 0 (No OAQ)
This signifies that there is no outdoor air sensor installed. The
default value of OAQ is 400 ppm CO
controlled ventilation (DCV).
OA.CF = 1 (DCV)
The outdoor air quality sensor analog input is the value of
OAQ for demand controlled ventilation (DCV).
OA.CF = 2 (OAQ Lockout)
The outdoor air quality analog input is only used to lock out the
outdoor ventilation. The economizer commanded position is
set to 0% when the CO ppm exceeds the OAQ lockout value
2
configured for the OAQ Lockout Limit (Configura-
 
tion AIR.Q OAQ.L). The default value for OAQ Lockout
Limit (OAQ.L) is 600 ppm CO

FAN ENABLE (ANALOG IAQ SENSOR)

The DCV algorithm will operate whenever the building is oc-
cupied and the indoor fan is operating or whenever the IAQ al-
gorithm has caused the indoor fan to operate. The IAQ Analog
Fan Config (Configuration
whether or not the IAQ algorithm can turn on the indoor fan. If
the indoor fan is not operating, the economizer position will be
zero. The damper position may exceed Econ Min at Max Fan

Speed (Configuration ECON
damper position curve to provide economizer cooling.
IA.FN = 0 (Never)
When IA.FN = 0, the IAQ algorithm can never turn on the fan.
 
AIR.Q
 
ECON MP.MX) and corre-
 
AIR.Q AQ.MN)

FS.MX). If IAQ is high, the
MP.MX) when the indoor fan is op-
OVR.P).
O.20M).
when using demand
2
.
2
 
AIR.Q IA.FN) determines

MP.MX) and corresponding
II.CF). IA.FN = 1 (Occupied)
When IA.FN =1, the IAQ algorithm will turn on the indoor fan
whenever the building is occupied and IAQ/OAQ differential
is greater than the Fan On AQ Differential (Configura-
 
tion AIR.Q
IAQ/OAQ differential is less than the Fan Off AQ Differential
(Configuration
IA.FN = 2 (Always)
The indoor fan operation for IA.FN = 2, is the same as the op-
eration when IA.FN =1, except the algorithm is not limited to
the occupied periods only. The fan can be triggered on when
the space is occupied or unoccupied.

FAN ENABLE (SWITCH INPUT)

The DCV algorithm will operate whenever the building is oc-
cupied and the indoor fan is operating or whenever the IAQ al-
gorithm has caused the indoor fan to operate. The IAQ Switch
Fan Config (Configuration
whether or not the IAQ algorithm can turn on the indoor fan. If
the indoor fan is not operating, the economizer position will be
zero. The damper position may exceed Econ Min at Max Fan
Speed (Configuration
damper position curve to provide economizer cooling.
II.FN = 0 (Never)
When the II.FN = 0, the IAQ algorithm can never turn on fan.
II.FN = 1 (Occupied)
When II.FN =1, the IAQ algorithm will turn on the indoor fan
whenever the building is occupied and IAQ is high. The indoor
fan will turn off when the IAQ returns to normal.
II.FN = 2 (Always)
The indoor fan operation for II.FN =2 is the same as the opera-
tion when IA.FN =1, except the algorithm is not limited to the
occupied periods only. The fan can be triggered on when the
space is occupied or unoccupied.
Optional Humidi-MiZer
Units with the factory-equipped Humidi-MiZer option are capa-
ble of providing multiple modes of improved dehumidification
as a variation of the normal cooling cycle. The Humidi-MiZer
option includes additional valves in the liquid line and discharge
line of each refrigerant circuit, a reheat coil downstream of the
evaporator, and Motormaster
all outdoor fans. The Humidi-MiZer Equipped (Configura-
 
tion HMZR
Humidi-MiZer equipped units. This enables Humidi-MiZer op-
erating modes and service test.
Humidi-MiZer operation requires installation and configuration
of either a space relative humidity sensor or a relative humidity
switch input.
 
tion UNIT
switch or 2 for normally closed switch. The switch is wired to
field connection terminal board terminal labeled HUM and the
"R2" terminal. Set RH Sensor on OAQ Input (Configura-
 
tion UNIT
sensor wired to field connection terminal board (TB) terminals
SPRH and LPWR (for loop powered). RH Sensor Value at 4ma
(Configuration
input from the relative humidity sensor. RH Sensor Value at
20ma (Configuration
a 20mA input from the relative humidity sensor.

DEHUMIDIFICATION DEMAND

When using a humidistat or switch input, the demand for de-
humidification is seen as Space Humidity Switch (In-

puts GEN.I
means humidity level is good and a high value means that
dehumidification is needed.When using an RH sensor, the
demand is based on the Space Humidity Sensor (In-
 
puts AIR.Q
28
DF.ON). The indoor fan will turn off when the
 
AIR.Q DF.OF).
 
AIR.Q
 
ECON MP.MX) and corresponding
®
Dehumidification System
® variable-speed control of some or
REHT) configuration is factory set to Yes for
Space Humidity Switch
RH.SW) set to 1 for use of a normally open
RH.S) to Yes for use of a 4 to 20 mA output RH
 
AIR.Q H.4M) sets the % display for a 4mA
 
AIR.Q H.20M) sets the % display for

HUM) being Low or High. A low value
SP.RH) value compared to the Space RH
II.FN) determines
(Configura-