Johnson Controls ZY Series User Manual

Table 60: Smart Equipment
™
UCB - limit, 24 VAC power, and shutdown connections
Location Label Description Function and comments
LIMIT
Monitored 24 VAC input through heat section limit
switch(es)
If voltage is absent, indicating the heat section is over-temperature, the UCB will bring on the
indoor blower
C
24 VAC, 75 VA transformer Common referenced to
cabinet ground
Connects through circuit traces to thermostat connection strip C and indoor blower VFD pin C
24 V 24 VAC, 75 VA transformer hot Powers the UCB microprocessor, connects through circuit trace to the SD 24 terminal
SD 24
24 VAC hot out for factory accessory smoke detector,
condensate overflow and/or user shutdown relay
switching in series
Connects through circuit trace to thermostat connection strip SD-24. A wiring harness jumper
plug connecting SD 24 to SD R is in place if factory accessories for unit shutdown are not used -
this jumper plug must be removed if the switching of field-added external accessories for unit
shutdown are wired between thermostat connection strip SD-24 and R
SD R
24 VAC hot return from factory accessory smoke
detector, condensate overflow and user shutdown relay
switching in series
Connects through circuit trace to the R terminal on the upper left of the board
B
R 24 VAC hot for switched inputs to the UCB
Connects through circuit trace to the thermostat connection strip R terminal, right FAN OVR pin,
right HPS1 pin, right HPS2 pin, lower DFS pin and lower APS pin
Table 61: Smart Equipment
™
UCB - space temperature sensor connections
Location Label Description Function and comments
ST
Space Temperature sensor input from 10KΩ @ 77°F, Type III
negative temperature coefficient thermistor
Positive of VDC circuit (3.625 VDC reading to COM with open circuit), effective if “Thermo-
stat-only Control” parameter is set OFF, space sensor override momentary shorts ST to
COM to initiate/terminate temporary occupancy
COM Common for ST and SSO inputs Negative of VDC circuit for ST and SSO inputs
C
SSO Space Sensor Offset input from 0 to 20KΩ potentiometer
Positive of VDC circuit (3.625 VDC reading to COM with open circuit), 10KΩ/2.5 VDC is 0°F
offset, 0Ω/0 VDC is maximum above offset and 20KΩ/3.4 VDC is maximum below offset
from active space temperature setpoint
Table 62: Smart Equipment
™
UCB - temperature sensor connections
Location Label Description Function and comments
SAT+
Supply Air Temperature sensor input from 10KΩ @ 77°F, Type
III negative temperature coefficient thermistor
Input required for operation; 3.625 VDC reading SAT+ to SAT– with open circuit. Used in
heat/cool staging cutouts, free cooling operation, demand ventilation operation, comfort
ventilation operation, economizer loading operation, VAV cooling operation, hydronic heat
operation.
RAT+
Return Air Temperature sensor input from 10KΩ @ 77°F, Type
III negative temperature coefficient thermistor
Input required for operation; 3.625 VDC reading RAT+ to RAT– with open circuit. Used
in return air enthalpy calculation. Substitutes for space temperature if no other space
temperature input is present.
OAT+
Outside Air Temperature sensor input from 10KΩ @ 77°F,
Type III negative temperature coefficient thermistor
Input required for operation but may be a communicated value; 3.625 VDC reading OAT+
to OAT– with open circuit. Used in heat/cool cutouts, low ambient cooling determination,
dry bulb free cooling changeover, outside air enthalpy calculation, economizer loading
operation, heat pump demand defrost calculation.
CC1+
#1 refrigerant circuit Condenser Coil temperature sensor
input from 10KΩ @ 77°F, Type III negative temperature
coefficient thermistor
Input required for heat pump units, not required for A/C units; 3.625 VDC reading CC1+ to
CC1– with open circuit. Used in heat pump demand defrost calculation.
EC1+
#1 refrigerant circuit Evaporator Coil temperature sensor
input from 10KΩ @ 77°F, Type III negative temperature
coefficient thermistor
Input required for operation; 3.625 VDC reading EC1+ to EC1– with open circuit. Used in
suction line temperature safety.
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.
D
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.
INSTALLATION MANUAL ZY SERIES 3-10ton 60 Hertz R-410A 105
Johnson Controls Ducted Systems

Johnson Controls ZY Series Specifications

General

Brand	Johnson Controls
Model	ZY Series
Category	Air Conditioner
Language	English