Installation Guide
69-2200—03 4
The DS/BK terminal is used with a variable-speed fan.
Connect to the DS, BK, or ODD terminal on the furnace
equipment. When only one zone calls for heat, cool, or
fan, the DS/BK terminal operates the fan at low speed
to reduce airflow.
7
Connect transformer as shown.
Connect equipment as shown.
6
WIRING
DEDICATED TRANSFORMER
R
C
M28237
R
C
POWER
L1
(HOT)
L2
M28236A
EQUIPMENT
R
C
E/Aux
Y
G
O
B
DS/BK
L
AIR
HANDLER
FAN RELAY
AUX/EM HEAT
HEAT PUMP
G
Y
24 VOLT TRANS.
C
R
Y
E
C
R
REVERSING
VALVE
M27339B
AIR
HANDLER
FAN RELAY
AUX HEAT
HEAT PUMP
G
Y
24 VOLT TRANS.
C
R
Y
E
C
R
REVERSING
VALVE
ZD DAMPER
SPRING-OPEN
POWER-CLOSED
PURGE OVERRIDE
EQUIPMEN
T
M4 OPEN
M6 CLOSED
M1 COMMON
R
C
E/AUX
Y
G
O/B
L
RRD OR MARD
DAMPER
POWER-OPEN
POWER-CLOSED
M1
M4
M6
R
C
E/AUX
Y
G
O
L
THERMOST
AT
ZONE 1
DAMPER
DEDICATED
TRANSFORMER
L1
(HOT)
L2
R
C
C7735A1000
DATS
DATS
R
C
ZONE 1
ZONE 2
EM HEAT
EMERGENCY HEAT
POWER
SENSO
R
HEAT
COOL
FAN
PURGE
R
C
E/AUX
Y
G
O/B
L
M1
M4
M6
ZONE 2
DAMPER
THERMOST
AT
R
C
E/AUX
Y
G
O
L
R
C
E/Aux
Y
G
O
B
DS/BK
L
The following diagram is an overall view of wiring for a heat pump system as depicted in steps 3–7.
Thermostats must be wired/configured for cool changeover “O”, even if equipment uses heat changeover “B.”
