York YD480 Series Installation Manual page 24

5012886-YIM-B-0517
Table 9: Smart Equipment™ UCB Details (Continued)
R
W1
W2
Y1
Y2
G
OCC
X
R
SD-24
C
POWER
FAULT
SA BUS
ST
COM
SSO
24
Description
24 VAC hot for switched inputs to the UCB
Terminal Thermostat connection strip on left edge of UCB
1st stage heating request, 24 VAC input switched
from R
2nd stage heating request, 24 VAC input switched
from R
1st stage cooling request, 24 VAC input switched
from R
2nd stage cooling request, 24 VAC input switched
from R
Continuous indoor blower request, 24 VAC input
switched from R
Occupancy request, 24 VAC input switched from
R
Hard lockout indicator, 24 volt output to a light
thermostat LED
24 VAC hot for thermostat switching and power
If field-added external accessories for unit
shutdown are used, 24 VAC hot out for smoke
detector, condensate over- flow and/or user
shutdown relay switching in series
24 VAC common for thermostat power
Green UCB power indicator
Red hard lockout, networking error and firmware
error indicator
Green UCB SA bus communication transmission
indicator
Terminal Space temperature sensor connections at center on upper edge of UCB
Space Temperature sensor input from 10KΩ @
77°F, Type III negative temperature coefficient
thermistor
Common for ST and SSO inputs
Space Sensor Offset input from 0 to 20KΩ
potentiometer
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
Not effective for cooling-only units
Not effective for cooling-only units or units with single-stage
heat sections
Visible in the display menu when the #ClgStgs parameter is set
for 2 or more, also effective for economizer free cooling supply
air temperature reset when the #ClgStgs parameter is set for 1
or more
Must have the OccMode parameter set for External to be
effective
If field-added external accessories for unit shutdown are used,
24 VAC hot return from smoke detector, condensate overflow
and/or user shutdown relay switching in series
Unit wiring harness jumper plug for factory shutdown
accessories must be removed if the switching of field-added
external accessories for unit shutdown are wired between
thermo- stat connection strip SD-24 and R
LEDs on left edge of UCB
Lit indicates 24 VAC is present at C and 24V terminals
1/2 second on/off flashing indicates one or more alarm is
currently active, 1/10th second on/off flashing indicates a
networking error (polarity, addressing, etc.) or a firmware error
(likely correctable with re-loading from USB flash drive)
Lit/flickering indicates UCB SA bus communication is currently
active, off indicates the
UCB is awaiting SA bus communication
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 & Comments
Johnson Controls Unitary Products