Radio Thermostat CT50 Install Manual - page 17
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Wire Reference Chart
Possible Wires What They Control
R or V or VR
RH and RC Single power for HEAT and COOL
RH or 4
RH Power for HEAT (RH not connected to RC jumper clip removed)
RC
RC Power for COOL (RH not connected to RC jumper clip removed)
W
W Heat control
W2
W2 2nd stage HEAT or heat pump auxiliary heat
W3
W3
3rd stage HEAT or 2nd stage of 2 stage auxiliary heat
Y
Y COOL control or 1st stage compression for heat pump
Y2
Y2 2nd stage COOL control or 2nd stage compression for a heat pump
G or F
G FAN control
C or X
C 24VAC power (to power thermostat)
NOTE: TRANE uses B for this connection
H
H
External Humidifier
DH
DH External De-Humidifier
EX
EX
external fresh air baffle
B
B Heat pump changeover (cool to heat, powered in heat)
O
O Heat pump changeover (heat to cool, powered in cool)
B and O
IMPORTANT: If there are both B and O wires (Trane pump
products) DO NOT CONNECT B to B terminal, connect B to C
terminal. If not a Trane product tape off B.
E
n/a Emergency heat (do not connect, tape off)
L
n/a System monitor (do not connect, tape off)
T
n/a Outdoor sensor (do not connect, tape off)