5566019-BIM-B-1118
Johnson Controls Ducted Systems 67
D
CC2+
#2 refrigerant circuit Condenser Coil temperature
sensor input from 10KΩ @ 77°F, Type III negative
temperature coefficient thermistor
Input required for 2-compressor heat pump units, not required for 2-
compressor A/C units, not active for 1-compressor units; 3.625 VDC
reading CC2+ to CC2– with open circuit. Used in heat pump demand
defrost calculation.
EC2+
#2 refrigerant circuit Evaporator Coil temperature
sensor input from 10KΩ @ 77°F, Type III negative
temperature coefficient thermistor
Input required for operation of 2-compressor units, not active for 1-
compressor units; 3.625 VDC reading EC2+ to EC2– with open circuit.
Used in suction line temperature safety.
Smart Equipment™ UCB - temperature sensor connections (continued)
Location Label Description Function and comments
Smart Equipment™ UCB - pinned connections
Location Label Description Function and comments
E
RAH+
Return Air Humidity input from 0-10 VDC @ 0-
100% RH sensor
Input required for reheat units, optional in all other units, may be a
communicated value. Used in return air enthalpy calculation,
temperature/humidity setpoint reset, reheat operation.
DCT PRS+
Supply Duct Pressure input from 0-5 VDC @ 0-5”
w.c. sensor
Input required for variable air volume units. Used in VAV indoor blower
operation.
DFS
(upper pin)
24 VAC hot return from Dirty Filter Switch
Optional input; switch closure for greater than 15 seconds during
indoor blower operation initiates a notification alarm
DFS
(lower pin)
24 VAC hot out for Dirty Filter Switch Connects through circuit trace to the R terminal
APS
(upper pin)
24 VAC hot return from Air Proving Switch
When this optional input is enabled: the air proving switch must close
within 30 seconds of initiation of indoor blower operation and not open
for greater than 10 seconds during indoor blower operation to allow
heat/cool operation and prevent an “APS open” alarm; the air proving
switch must open within 30 seconds of termination of indoor blower
operation to prevent an “APS stuck closed” notification alarm
APS
(lower pin)
24 VAC hot out for Air Proving Switch Connects through circuit trace to the R terminal
C
Common for the VFD output Negative of the VDC circuit for the VFD output
VFD
2-10 VDC (0-100%) output for the indoor blower
Variable Frequency Drive
Output is active with indoor blower operation. For CV units: this output
provides stepped IntelliSpeed control of the indoor blower VFD based
on fan-only, cooling stage and heating stage outputs. For VAV units:
this output provides control of the indoor blower VFD based on supply
duct static pressure input and setpoint.
VFDFLT
24 VAC hot input from the normally open VFD
alarm contact
The VFD alarm contact switches from R within the unit wiring harness.
24 VAC input results in unit shutdown and a “VFD fault” alarm
Smart Equipment™ UCB - USB connector
Location Label Description Function and comments
F J10
Type A female Universal Serial Bus connector
Used for backup, restoration, & copying of board parameters as well as
board software updating through a flash drive
J15
Factory wired SA Bus connector
Smart Equipment™ UCB - 24 V terminal
Location Label Description Function and comments
G 24V FOR OUTPUTS
24 VAC hot for H1, H2, CN-FAN, AUX HGR,
FAN C1 and C2 output relay contact switching
Output relay circuitry is isolated from other UCB components
and the 24 VAC hot source may be from a second
transformer in the unit
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