wire on your valve may be called, 6, Y, or G (see “Wire reference chart” on page
16).
Figure 16: Three-wire zoned hot water
C B O W W2 Y Y2 RH RC G A
Thermostat
Motor valve
W
R
A
C B O W W2 Y Y2 RH RC G A
Thermostat
Solenoid valve
W
R
A
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 two-stage auxiliary heat.
Y
Y cool control or 1st-stage of compression for heat pump.
Y2
Y2 2nd-stage cool control or 2nd-stage compression for heat
pump.
G or F
G fan control.
C or X
C 24 VAC power (to power thermostat). Note: Trane uses B for
this connection.
H
H external humidifier.
DH
DH external dehumidifier.
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
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).
16
IS-ZW-TSTAT-300 Advanced Thermostat Installation Guide
