9
HEATING/COOLING SYSTEMS
5 + 6 Wire 2 Transformers
COMMON FOR SYSTEM POWER
2 + 3 WIRE HEATING SYSTEMS
COMMON FOR SYSTEM POWER
HEATING/COOLING SYSTEMS
4 + 5 Wire 1 Transformers
COMMON FOR SYSTEM POWER
COOLING SYSTEMS
COMMON FOR SYSTEM POWER
C
RH
RC
O
B
G
Y
W
W
H
4
Y
C*
6
G
F
RC
R
RH
V
5
JUMPER
REMOVED
NOTE: "G" WIRE IS
OMITTED FOR
2 WIRE SYSTEMS
B*
O
C
RH
RC
O
B
G
Y
W
RH
RC
R
V
5
G
F
W
H
4
JUMPER
PROVIDED
C
RH
RC
O
B
G
Y
W
W
H
4
Y
C*
6
G
F
RH
RC
R
V
5
B*
O
C
RH
RC
O
B
G
Y
W
RH
R
V
G
F
Y
C*
6
JUMPER
PROVIDED
JUMPER
PROVIDED
WIRING DIAGRAM NOTES (APPLIES TO ALL DRAWINGS)
* The DASHED lines are optional depending upon your system type.
* Verify whether “C”, “X” or “B” wires are connected to system common.
* If “B” and “O” are both present, it is likely that “B” is a system common.
* If a “B” wire in your system is a common, then connecting it to the “B” terminal may cause damage
to your system.
* If “Y” and “C” are both present, it is likely that “C” is a system common.
* Use an optional common wire to allow the system to power your thermostat.
3.6. WIRING DIAGRAMS
