5703827-XIM-A-0319
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Johnson Controls Ducted Systems
Smart Equipment™ UCB - heat section connections
Location Label
Description
Function and comments
H
H1
24 VAC hot output for heat section stage 1
Not effective for cooling-only units. Output if demand is present and
permissions allow one stage or two stages of heat section operation
H2
24 VAC hot output for heat section stage 2
Not effective for cooling-only units or units with single-stage heat sections.
Output if demand is present and permissions allow two stages of heat
section operation
MV
24 VAC hot input confirming heat section
operation
Sourced from gas valve in gas heat units or first stage heat contactor in
electric heat units. Input within 5 minutes from initiation of H1 output initiates
the “Heat On Fan Delay” timer, loss of input following the termination of H1
output initiates the “Heat On Fan Delay” timer, no input within 5 minutes
from initiation of H1 output initiates an “Ignition Failure” alarm, input for
longer than 5 minutes without H1 output initiates a “Gas Valve Mis-wire”
alarm
Smart Equipment™ UCB - pin cooling and fan output
Location
Label
Description
Function and comments
I
CN-FAN
24 VAC hot output for the condenser fan contactor
coil
Output with either C1 or C2 output; interrupted during defrost cycle for
heat pump units
AUX HGR
24 VAC hot output for hot gas reheat components Effective only for reheat units, output with reheat operation
FAN
24 VAC hot output for indoor blower contactor coil/
indoor blower VFD enable relay coil
Output with heat/cool operation, G input or schedule demand
C1
24 VAC hot output for compressor 1
If demand is present and permissions allow compressor 1 operation;
output with compressor cooling, comfort ventilation cooling, reheat or
heat pump heating demands
C2
24 VAC hot output for compressor 2
Not effective for one stage compressor UCBs. If demand is present
and permissions allow compressor 2 operation; output with compressor
cooling, comfort ventilation cooling or heat pump heating demands
Smart Equipment™ UCB - refrigerant circuit safety switch and indoor blower overload connections
Location
Label
Description
Function and comments
J
HPS1
(right pin)
24 VAC hot out for refrigerant circuit 1 High
Pressure Switch
Connects through circuit trace to the R terminal
HPS1
(left pin)
24 VAC hot return from refrigerant circuit 1 High
Pressure Switch
Input is only considered if C1 output is needed; input must be present
to allow C1 output. Three HPS1 trips in a two hour period cause a
“High Pressure Switch 1 Lockout” and C1 output is then prevented
until alarm reset. Connects through circuit trace to the right LPS1 pin.
LPS1
(right pin)
24 VAC hot out for refrigerant circuit 1 Low
Pressure Switch
Connects through circuit trace to the left HSP1 pin
LPS1
(left pin)
24 VAC hot return from refrigerant circuit 1 Low
Pressure Switch
Input is only considered after 30 seconds of C1 output; afterwards,
input must be present to allow C1 output. Three LPS1 trips in a one
hour period cause a “Low Pressure Switch 1 Lockout” and C1 output
is then prevented until alarm reset.
HPS2
(right pin)
24 VAC hot out for refrigerant circuit 2 High
Pressure Switch
Not effective for one stage compressor UCBs. Connects through
circuit trace to the R terminal
HPS2
(left pin)
24 VAC hot return from refrigerant circuit 2 High
Pressure Switch
Not effective for one stage compressor UCBs. Input is only
considered if C2 output is needed; input must be present to allow C1
output. Three HPS2 trips in a two hour period cause a “High Pressure
Switch 1 Lockout” and C2 output is then prevented until alarm reset.
Connects through circuit trace to the right LPS2 pin.
