Honeywell TB7220U Installation Instructions Manual page 3

Terminal Designation
RC (see Note 1)
R (see Note 1)
Y
C (see Note 2)
W
G
W2
Y2
O/B (see Note 3)
S1 (See Note 4)
S2 (See Note 4)
NOTES:
1. When used in a single-transformer system,
leave metal jumper wire in place between RC
and R. If used on a two-transformer system,
remove metal jumper wire between RC and
R.
2. Common wire is optional when thermostat is
used with batteries. When using separate
transformers for heating and cooling, the
common must come from the cooling
transformer.
3. If thermostat is configured for a heat pump in
the Installer Setup, configure changeover
valve for cool (O-factory setting) or heat (B).
4. Sensor wires must have a cable separate
from the thermostat control cable.
Table 2. Terminal Designation Descriptions.
Power for cooling—connect to secondary side of cooling system transformer.
Power for heating—connect to secondary side of heating system transformer.
Compressor output.
Common wire from secondary side of cooling system transformer.
Heat relay.
Fan relay.
Second stage heat relay.
Second stage cooling.
Changeover valve for heat pumps.
Optional outdoor or indoor remote sensor.
Optional outdoor or indoor remote sensor.
TB7220U ULTRASTAT PROGRAMMABLE THERMOSTAT
Description
Table 3. Wiring Diagrams.
System Type
Standard Heat/Cool
Heat Only
Heat Only with Fan
Cool only
Standard Multistage
up to 2 Heat/2 Cool
Heat Pump
(No Auxiliary Heat)
Heat Pump
(with Auxiliary Heat)
Multiple T7770A Sensors
Multiple C7189U Sensors
3
Wallplate Wiring
Terminal Diagram
Identifications Figure
Conventional 6, 7
Conventional 8
Conventional 9
Conventional 10
Conventional 11, 12
Heat Pump 13, 14
Heat Pump 15, 16
— 17, 18, 19
— 20
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