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12
INITIAL
SETUP
for more information on the internal BACnet explorer screen. For an explanation of the features listed above,
3.5 Digital Outputs (DO)
The various control outputs required by heat and cool stage control are mapped to physical terminal blocks on the con-
troller via mechanical relays. The mapping depends on the mode of operation for the controller, and can even change
dynamically during normal operation in heat pump mode. The relays’ terminals are described by the color of wire that is
traditionally used for that control wire:
Figure 2
Terminal
Designator
Color
Function
R
Red
24V HVAC Unit Power
W
White
Heat
Y
Yellow
Cool
G
Green
Fan
B/O
Blue/Orange
Reversing Valve
TC
n/a
Time Clock
Mapping is done as shown in the table below, based on system type (conventional or heat pump), and mode of operation.
If the fourth stage of heat or cool is desired in conventional mode, then the third stage must also be enabled.
Both of these stages are optional and must be configured using the internal BACnet Explorer.
Figure 3
Terminals (Relays)
Conventional
US4010/US4110 Only
Conventional
(Fan Powered Box)
Heat Pump
(Normal)
Heat Pump
(Low Limit
Changeover)
Heat Pump
(Emergency
Heat)
W1
Heat 1
Heat 1
Heat 3
Heat 1
Heat 1
W2 *
Heat 2
Heat 4
Heat 2
Heat 2
Y1
Cool 1
Heat 2
Heat 1/Cool 1
Cool 1
Y2 *
Cool 2
Heat 2/Cool 2
Cool 2
G
Fan
Fan
Fan
Fan
Fan
B/O
Heat/Cool 3, 4 *
Reversing Valve
Reversing Valve
Reversing Valve
TC
Heat/Cool 3, 4 *
*
Time Clock (TC): When used as a time clock output, this relay opens or closes based on the occupancy state. This relay
is isolated from other heating and cooling relays, which share a common connection with the R terminal. If this output is
used as a heating or cooling stage, the R terminal must be jumpered to one of the TC terminals. This is an open or close
relay that will support 24V.
Reversing Valve (B/O): When the UbiquiSTAT is in heat pump mode, the B/O terminal is used as a reversing valve output.
It may be configured as open or closed for cooling (the default is closed) via the polarity property. This can only be done
through communications. It cannot be changed from the keypad. If the UbiquiSTAT is configured as conventional, it may
be used as an additional heating or cooling stage.