York ZKT06 Installation Manual page 61

Smart Equipment™ UCB - limit, 24 VAC power, and shutdown connections
Location Label
Monitored 24 VAC input through heat section
LIMIT
limit switch(es)
24 VAC, 75 VA transformer Common
C
referenced to cabinet ground
24V 24 VAC, 75 VA transformer hot
24 VAC hot out for factory accessory smoke
B
detector, condensate overflow and/or user
SD 24
shutdown relay switching in series
24 VAC hot return from factory accessory
SD R smoke detector, condensate overflow and
user shutdown relay switching in series
R 24 VAC hot for switched inputs to the UCB
Smart Equipment™ UCB - space temperature sensor connections
Location Label
Space Temperature sensor input from 10KΩ @
ST 77°F, Type III negative temperature coefficient
thermistor
C COM Common for ST and SSO inputs
Space Sensor Offset input from 0 to 20KΩ
SSO
potentiometer
Smart Equipment™ UCB - temperature sensor connections
Location Label
Supply Air Temperature sensor input from 10KΩ
SAT+ @ 77°F, Type III negative temperature coefficient
thermistor
Return Air Temperature sensor input from 10KΩ
RAT+ @ 77°F, Type III negative temperature coefficient
thermistor
Outside Air Temperature sensor input from 10KΩ
D
OAT+ @ 77°F, Type III negative temperature coefficient
thermistor
#1 refrigerant circuit Condenser Coil temperature
CC1+ sensor input from 10KΩ @ 77°F, Type III negative
temperature coefficient thermistor
#1 refrigerant circuit Evaporator Coil temperature
EC1+ sensor input from 10KΩ @ 77°F, Type III negative
temperature coefficient thermistor
Johnson Controls Ducted Systems
Description
Description
Description
Function and comments
If voltage is absent, indicating the heat section is over-temperature, the UCB will
bring on the indoor blower
Connects through circuit traces to thermostat connection strip C and indoor
blower VFD pin C
Powers the UCB microprocessor, connects through circuit trace to the SD 24
terminal
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
Connects through circuit trace to the R terminal on the upper left of the board
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
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
Negative of VDC circuit for ST and SSO inputs
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
Function and comments
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.
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.
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.
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.
Input required for operation; 3.625 VDC reading EC1+ to EC1– with open
circuit. Used in suction line temperature safety.
5121835-TIM-J-1118
Function and comments
61