Johnson Controls YP9C Series Installation Manual page 12

5750151-UIM-G-0423
CFM Light
Diagnostic Light
Figure 14: Furnace control board – communications connections
Control wiring using communicating
controls (non-variable capacity outdoor models)
Use the wiring diagram below to connect the furnace control, Communi-
cating Control (wall thermostat) and communicating outdoor unit. Be
sure that all of the "A" terminals are connected together, all of the "B"
terminals are connected together, all of the "GND" or "C" terminals are
connected together and all of the "R" terminals are connected together.
See Figure 15. When using a fully communicating system, the large
screw terminals (C, G, R, etc.) on the furnace control are not used. The
four small screw terminals in the terminal block on the end of the fur-
nace control should be used.
Touch Screen Modulating Furnace
Communicating control Communicating control
A+
R
C
B-
Figure 15: Modulating furnace with communicating AC or HP
12
Air Conditioner/Heat Pump
Communicating control
A+ A+
R R
GND or C GND
B- B-
LO
COMP
HI
COMP
O
DHUM
Y1
Y/Y2
W
R
G
C
Touch Screen Modulating Furnace
Communicating control Communicating control
A+
R
C
B-
Figure 16: Modulating furnace with communicating thermostat and
non-communicating AC
Important: Do not place more than one wire under any single
communication terminal screw (there are four communication
terminal screws). If more than one wire must be connected to a
terminal screw, attach only the terminal end of a one wire pigtail
no longer than 6 in., and use a wire connector to connect the
other end of the pigtail to the other wires. Failure to do this will
result in nuisance communication error faults. See Figure 17.
Non- Communicating
Air Conditioner
A+
R
GND or C
B-
LO
Y
COMP
HI
Y2
COMP
O R
DHUM C
Y1
Y/Y2
W
R
G
C
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