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DEFROST
JUMPER NEEDED
FOR HEAT PUMP
DHUM DEHUMIDIFY
APPLICATIONS
HUM HUMIDIFY
O REVERSING VALVE COOL
B REVERSING VALVE HEAT
RH HEATING TRANSFORMER
RC COOLING TRANSFORMER
SEE
FIGURES FOR
EQUIPMENT
WIRING
G FAN
W2 HEAT STAGE 2
W1 HEAT STAGE 1
Y2 COMPRESSOR STAGE 2
Y1 COMPRESSOR STAGE 1
24 VAC
C
ZONING
RZ
TRANSFORMER
CLS1
ZONE 1
COM1
DAMPER
OPN1
CLS2
ZONE 2
COM2
DAMPER
OPN2
8
1
NOTES:
†
†
Carrier's Comfort Heat system is now supported by Comfort Zone
II -B, with all the features of the Thermidistat™ Control. When
used with compatible variable-speed furnaces and fan coils,
controlled dehumidification in cooling and warm heat pump
heating are provided.
Step 9—Understanding Sequence of Operation
TEMPERATURE SET POINTS
The Comfort Zone II -B System uses 2 temperature set points for
each zone, the higher for cooling and the lower for heating. A
minimum difference of 2°F. is normally enforced between heating
and cooling set points, although this value may be adjusted by the
installer. Each set point may be manually adjusted or controlled by
a programmed time schedule established by the home or business
owner.
HEATING AND COOLING COMFORT SET POINTS
If space temperature is between heating and cooling set points for
the zone, then the zone is said to be "satisfied" with respect to
temperatures. When a zone is satisfied, no heating or cooling is
required. When all zones are satisfied, there is no demand and the
equipment is turned off. For example, if cooling set point is 76°F
and heating set point is 72°F, then a space temperature of 73°F is
assumed to be satisfactory and no heating or cooling of the zone is
required.
If space temperature in a zone falls below heating set point, then
that zone needs to have heat added to zone which will raise space
temperature back to heating set point. For example, if heating set
point is 72°F and space temperature is 70°F, then space tempera-
2 ZONE EQUIPMENT CONTROLLER
DEF DEFROST
DAMPER
DAMPERS
CLS_
=
CLOSE
COM_
=
COMMON = 24VAC FROM RZ
OPN_
=
OPEN
OPTION
SWITCHES
NOTE SWITCH
#8 IS AT TOP
*
= OPTIONAL COMPONENTS
= INSTALLING ZONE 1 REMOTE SENSOR AT OS1 AND OS1C WILL OVERRIDE
TEMPERATURE SENSOR ON USER INTERFACE
= COMMUNICATION BUS ARE IN PARALLEL WITH EACH OTHER
(EITHER CONNECTOR CAN BE USED)
Fig. 9—2-Zone System Wiring Diagram
FUSE
3A
D20
(LED)
†
COMMUNICATION
BUS
†
COMMUNICATION
BUS
REMOTE
SENSORS
ture must be raised 2°F in order for zone to be satisfied. In this
case, temperature "heating demand" for zone is 2°F. (72° minus
70°F.)
Otherwise, if space temperature in a zone rises above cooling set
point, then that zone needs to have heat removed from zone which
will lower space temperature back to cooling set point. For
example, if cooling set point is 76°F and space temperature is
77°F, space temperature must be lowered 1°F in order for zone to
be satisfied. In this case, "cooling demand" for zone is 1°F. (77°
minus 76°F.)
OUT FEATURE
A new feature called OUT can be selected via the OUT button.
When this selection is made, the system is being told that the
selected zone is unoccupied. It will normally supply no condition-
ing to an OUT zone. If zone temperature exceeds 85°F or goes
below 60°F, conditioning will be supplied to maintain the zone
within these limits.
OUT zones are also used to provide dehumidification when
cooling is not needed. During 'cool to dehumidify' all OUT zones
are fully open.
The system will also use OUT zones to relieve the equipment
under overload conditions. If the total demand from all zones is
such that airflow is insufficient (or bypassing is excessive) this
condition will be sensed by the LAT or HPT temperature sensors.
When these temperatures begin to approach their limits, Comfort
Zone II -B will first begin to open dampers in the OUT zones to
relieve overload condition. The system will also monitor tempera-
tures in the OUT zones and never allow them to become cooler
6
P
NA
WIRELESS
D
RECEIVER*
C
NA
G
OAT
OUTDOOR AIR
TEMP SENSOR
OATC
LAT
LEAVING AIR
TEMP SENSOR
LATC
HPT
HEAT PUMP
TEMP SENSOR
HPTC
V+
RS+
BLUE/YELLOW
RS-
VG
V+
RS+
BLUE/YELLOW
RS-
VG
OPTIONAL
OS1
ZONE 1
OS1C
†
SENSOR
ZS2
ZONE 2
ZS2C
SENSOR
USER INTERFACE
RED
V+
RS+
GREEN
RS-
WHITE
VG
SMART SENSORS*
RED
V+
RS+
GREEN
RS-
WHITE
VG
A98082
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