5326602-XIM-B-1019
58
Johnson Controls Ducted Systems
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
Pin Refrigerant circuit safety switch and indoor blower overload connections at center on lower edge of UCB
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.
LPS2
(right pin)
24 VAC hot out for refrigerant circuit 2 Low
Pressure Switch
Not effective for one stage compressor UCBs. Connects
through circuit trace to the left HSP2 pin
LPS2
(left pin)
24 VAC hot return from refrigerant circuit 2 Low
Pressure Switch
Not effective for one stage compressor UCBs. Input is only
considered after 30 seconds of C2 output; afterwards, input
must be present to allow C2 output. Three LPS2 trips in a one
hour period cause a “Low Pressure Switch 2 Lockout” and C2
output is then prevented until alarm reset.
FAN OVR
(right pin)
24 VAC hot out for indoor blower FAN Overload
relay contact/motor protector switch
Connects through circuit trace to the R terminal
FAN OVR
(left pin)
24 VAC hot return from indoor blower FAN
Overload relay contact/motor protector switch
Input is only considered if FAN output is needed; input must be
present to allow FAN output and unit operation. One FAN OVR
trip lasting longer than 5 minutes or three FAN OVR trips in a
two hour period cause a “Fan Overload Lockout” and unit
operation is then prevented until alarm reset.
Terminal SA BUS connections on at left on lower edge and center of UCB
PWR
Power for SA (“Sensor-Actuator”) BUS devices
Also incorporated in the J8 6-pin phone jack connector at the
left-center of the board. Positive of the 15 VDC (reading to C)
circuit for powering an optional netstat and/or Multi Touch
gateway
C
Common for SA BUS power and communication
circuits
Also incorporated in the J8 6-pin phone jack connector at the
left-center of the board. Negative of the SA BUS circuits
–
Communication for SA BUS devices
Also incorporated in the J8 6-pin phone jack connector at the
left-center of the board. Positive of the VDC (typically, a
fluctuating 1.5 to 3.5 volts reading to C; at least 0.25 volts lower
than +) SA BUS communication circuit to optional economizer
board, 4-stage board, fault detection & diagnostics board,
netstat and/or Multi Touch gateway
Table 36: Smart Equipment™ UCB Details (Continued)
Description
Function & Comments
