T4
TR21
TR21
T
T
TR21
TR21
T
T
TR21
TR21
T
T
Fig. 5. Nine TR21 Sensors Providing a Temperature
Averaging Network for T7351 Thermostat.
WIRES THROUGH WALL
MOUNTING
HOLES
WALL
ANCHORS
(2)
Fig. 6. Mounting the Subbase.
Wiring
CAUTION
Electrical Shock or Equipment Damage Hazard.
Can shock individuals or short equipment circuitry.
Disconnect power supply before installation.
IMPORTANT
All wiring must comply with local electrical codes and
ordinances.
NOTE: Maximum (and recommended) wire size is 18-gauge
(ø 1.02 mm). Do not use wire smaller than 22-gauge
(ø 0.644 mm).
SUBBASE
T3
TR21
T
T
T
T
TR21
T
T
T
T
TR21
T
T
T
T
M29257
MOUNTING
SCREWS
M19608
T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT
Follow equipment manufacturer wiring instructions when
available. Refer to the Wiring Diagram section for typical
hookups. A letter code is located near each terminal for
identification. Refer to Tables 3 for terminal designations.
1. Loosen subbase terminal screws and connect system
wires.
2. Securely tighten each terminal screw.
3. Push excess wire back into the hole in the wall.
4. Plug the hole with nonflammable insulation to prevent
drafts from affecting the thermostat.
Table 3. T7351 Subbase for Three-stage Heat, Three-stage
Terminal
a
a
24 VAC Cooling transformer.
RC
RC
24 VAC Heating transformer.
a
a
RH
RH
X
X
Common.
aux
aux Auxiliary relay.
W1
O/B Conventional: Stage 1 heating relay.
Heat Pump: Changeover relay for heating (B) or
cooling (O)
W2
W1 Conventional: Stage 2 heating relay.
Heat Pump: 1st Stage auxiliary heat relay.
Y1
Y1
Conventional: Stage 1 cooling relay.
Heat Pump: Stage 1 compressor relay.
Y2
Y2
Conventional: Stage 2 cooling relay.
Heat Pump: Stage 2 compressor relay.
AS
AS
Discharge Air Sensor connection (1).
AS
AS
Discharge Air Sensor connection (2).
OS
OS
Outdoor Air Sensor connection (1).
OS
OS
Outdoor Air Sensor connection (2).
G
G
Fan relay.
T3
T3
TR20 Series Remote Sensor connection (1).
T4
T4
TR20 Series Remote Sensor connection (2).
T5
T5
TR20 Series Remote Sensor connection (5).
T6
T6
TR20 Series Remote Sensor connection (9).
T7
T7
TR20 Series Remote Sensor connection (7).
W3
W2 Conventional: Stage 3 heat or stage 4 cool relay.
Heat Pump: 2nd Stage auxiliary heat relay.
Y3
—
Conventional: Stage 3 cooling relay.
HS
HS
Humidity Sensor connection (signal: 0-10 Vdc).
TR23-H connection (11)
HC
HC
Humidity Sensor connection (common).
HP
HP
Humidity Sensor connection (power). TR23-H
connection (12)
M
M
Motion Sensor connection (1).
M
M
Motion Sensor connection (2).
5
Cool Systems.
Description
b
.
c
63-2666—02