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Q7300A,C,D,G Series 2000  
Commercial Thermostat Subbases  
INSTALLATION INSTRUCTIONS  
2
4 Vac single or multistage heat pump or conventional  
APPLICATION  
The Q7300 Thermostat Subbases are used with T7300  
Thermostats to provide electronic control of commercial  
heating and cooling systems. Select models have termi-  
nals for LEDs and remote temperature sensors. Refer to  
Table 1. All Q7300 Thermostat Subbases require a  
common wire to the supply power.  
Table 1. Description of Q7300 Subbases.  
Maximum Stagesa  
Model  
Q7300A  
Applications  
Conventional  
Heat Pump  
Thermostat Required  
T7300D, F  
Heat  
Cool  
Hookup Drawing  
2
3
3
3
2
2
2
3
9-12  
13-15  
16  
Q7300C  
T7300E, F  
Q7300D  
Heat Pump  
T7300E, F  
Q7300G  
Conventional  
T7300D, F  
17  
a
Depends on model.  
RECYCLING NOTICE  
If this control is replacing a control that contains  
mercury in a sealed tube, do not place your old  
control in the trash  
Location  
Subbase without Remote-Mounted  
Temperature Sensor  
Install the thermostat about 5 ft (1.5m) above the floor in  
an area with good air circulation at average temperature.  
See Fig. 1.  
Contact your local waste management authority for  
instructions regarding recycling and the proper  
disposal of the old thermostat.  
Do not install the thermostat where it can be affected by:  
—
—
—
—
—
drafts, or dead spots behind doors and in corners.  
hot or cold air from ducts.  
radiant heat from sun or appliances.  
concealed pipes and chimneys.  
unheated (uncooled) areas such as an outside wall  
behind the thermostat.  
INSTALLATION  
When Installing this Product…  
1.  
Read these instructions carefully. Failure to follow  
the instructions can damage the product or cause a  
hazardous condition.  
Subbase with Remote-Mounted  
2.  
Check the ratings given in the instructions and on  
the product to make sure the product is suitable for  
your application.  
Temperature Sensor(s)  
If only the remote-mounted temperature sensor(s) is used  
to sense and control room temperature, then install the  
thermostat in an area that is accessible for setting and  
adjusting the temperature and settings.  
3
.
.
Installer must be a trained, experienced service  
technician.  
After completing installation, use these instructions  
to check out the product operation.  
4
If both the subbase and remote-mounted temperature  
sensor(s) are used to sense and control room tempera-  
ture, then install the subbase about 5 ft above the floor in  
an area with good air circulation.  
®
U.S. Registered Trademark  
Copyright © 1996 Honeywell Inc. •  
•
All Rights Reserved  
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
YES  
NO  
NO  
5
FEET  
(1.5 METERS)  
NO  
M4823A  
Fig. 1. Typical location of thermostat or remote-mounted sensor.  
Install the remote-mounted sensor(s) about 5 ft (1.5m)  
above the floor in an area with good air circulation at  
average temperature. See Fig. 1.  
SUBBASE  
T
T
T7047C  
T
Do not mount the sensor(s) where it can be affected by:  
T
—
—
—
—
—
drafts, or dead spots behind doors and in corners.  
hot or cold air from ducts.  
radiant heat from sun or appliances.  
concealed pipes and chimneys.  
unheated (uncooled) areas such as an outside wall  
behind the thermostat.  
T7047G  
T7047C  
T
T
T
T
If more than one remote sensor are required, they must be  
arranged in a temperature averaging network consisting of  
two, three, four, five or nine sensors. See Fig. 2 through 6.  
M4839  
IMPORTANT  
To avoid electrical interference, which can cause  
erratic performance, keep wiring runs as short as  
possible and do not run thermostat wires  
adjacent to the line voltage electrical distribution  
systems. Use shielded cable (Belden type 8762  
or equivalent for 2-wire and Belden type 8772 or  
equivalent for 3-wire). The cable shield must be  
grounded only at the controlled equipment case.  
Fig. 3. Two T7047C Sensors and one T7047G Sensor  
providing temperature averaging network for  
T7300/Q7300 Thermostat/Subbase.  
SUBBASE  
T
T
T7047C  
T
T7047C  
T
T
T
SUBBASE  
T
T
T7047G  
T7047G  
T
T
T
T
T7047C  
T
T7047C  
T
T
T
M4838  
M4840  
Fig. 2. Two T7047G Sensors providing  
temperature averaging network for  
T7300/Q7300 Thermostat/Subbase.  
Fig. 4. Four T7047C Sensors providing  
temperature averaging network for  
T7300/Q7300 Thermostat/Subbase.  
62-0135  
2
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
SUBBASE  
T
T
WALL  
T7047G  
T7047G  
WIRES  
THROUGH WALL  
T
T
T
T
T7047G  
WALL  
ANCHORS  
(2)  
T
T
T7047G  
T7047G  
T
T
T
T
M4841  
MOUNTING  
HOLES  
Fig. 5. Five T7047G Sensors providing  
temperature averaging network for  
T7300/Q7300 Thermostat/Subbase.  
MOUNTING  
SCREWS  
M10237  
SUBBASE  
LEDS  
T
T
Fig. 7. Mounting the subbase.  
T7047C  
T
T7047C  
T
T7047C  
T
T
T
T
T
T
WIRING SUBBASE  
All wiring must comply with local electrical codes and  
ordinances. Follow equipment manufacturer wiring  
instructions when available. Refer to Fig. 9 through 17 for  
typical hookups. A letter code is located near each  
terminal for identification.  
T7047C  
T
T7047C  
T
T7047C  
T
T
T
CAUTION  
Disconnect power before wiring to prevent  
electrical shock or equipment damage.  
T7047C  
T
T7047C  
T
T7047C  
T
³
Loosen the terminal screws on the subbase and  
connect the system wires. See Fig. 8.  
T
T
IMPORTANT  
Use 18-gauge, solid-conductor color-coded  
thermostat cable for proper wiring. If using 18-  
gauge stranded wire, no more than ten wires can  
be used. Do not use larger than 18-gauge wire.  
M4842  
Fig. 6. Nine T7047C Sensors providing  
temperature averaging network for  
T7300/Q7300 Thermostat/Subbase.  
·
»
¿
Securely tighten each terminal screw.  
Push excess wire back into the hole.  
Plug the hole with nonflammable insulation to  
prevent drafts from affecting the thermostat.  
Mounting Subbase  
The subbase mounts horizontally on the wall or a 2 in. x 4 in.  
wiring box. Position the subbase horizontally on the wall or  
on a 2 in. x 4 in. wiring box.  
³
Position and level the subbase or wallplate (for  
appearance only). The thermostat functions properly  
even when not level.  
·
»
Use a pencil to mark the mounting holes. See Fig. 7.  
Remove the subbase or wallplate from the wall and  
drill two 3/16 inch holes in the wall (if drywall) as  
marked. For firmer material such as plaster or wood,  
drill two 7/32 inch holes. Gently tap anchors (pro-  
vided) into the drilled holes until flush with the wall.  
Position the subbase over the holes, pulling wires  
through the wiring opening.  
FOR STRAIGHT  
INSERTION STRIP  
¿
FOR WRAPAROUND  
5/16 IN. (8 MM).  
INSERTION STRIP  
/16 IN. (11 MM).  
7
M4826  
´
²
Loosely insert the mounting screws into the holes.  
Tighten mounting screws.  
Fig. 8. Proper wiring technique.  
3
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
Typical Wiring Hookups  
SUBBASE  
RC  
Y1  
G
X
W1 RH  
X4 X3 X1  
C5  
C4  
C3  
C2  
C1  
T
T
2
4
COMPRESSOR  
CONTACTOR  
EQUIPMENT  
MONITOR 2  
HEAT  
RELAY  
CA5  
CA4 CA3 CA2 CA1  
T
T
FAN  
RELAY  
T7147 REMOTE COMFORT ADJUST MODULE  
GND  
EQUIPMENT  
MONITOR 1  
3
1
L1  
HOT)  
L1  
(HOT)  
(
L2  
L2  
1
HEATING  
TRANSFORMER  
COOLING  
TRANSFORMER  
1
2
3
4
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
JUMPER RC TERMINAL TO RH TERMINAL WHEN INSTALLED ON A SYSTEM WITH ONE TRANSFORMER.  
CONNECT GND TO EARTH GROUND.  
INSTALL FIELD JUMPER BETWEEN X4 AND X TO POWER LEDS.  
M4939A  
Fig. 9. Typical hookup of T7300D,F/Q7300A in one-stage heat and  
one-stage cool conventional system with two transformers.  
SUBBASE  
RC  
Y1  
G
X
W2  
W1  
RH  
2
COMPRESSOR  
CONTACTOR 1  
HEAT  
RELAY 2  
FAN  
RELAY  
HEAT  
RELAY 1  
1
L1  
HOT)  
L1  
(HOT)  
(
L2  
L2  
1
HEATING  
TRANSFORMER  
COOLING  
TRANSFORMER  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
JUMPER RC TERMINAL TO RH TERMINAL WHEN INSTALLED  
ON A SYSTEM WITH ONE TRANSFORMER.  
M10230  
Fig. 10. Typical hookup of T7300D,F/Q7300A in two-stage heat and  
one-stage cool conventional system with two transformers.  
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
SUBBASE  
RC  
Y1  
G
Y2  
O
X
B
W2  
W1  
RH  
2
COMPRESSOR  
CONTACTOR 1  
COMPRESSOR  
CONTACTOR 2  
HEAT  
RELAY 2  
1
COOL  
DAMPER  
HEAT  
DAMPER  
HEAT  
RELAY 1  
FAN  
RELAY  
1
L1  
L1  
(HOT)  
(
HOT)  
L2  
L2  
COOLING  
TRANSFORMER  
HEATING  
TRANSFORMER  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
JUMPER RC TERMINAL TO RH TERMINAL WHEN INSTALLED ON A SYSTEM WITH ONE TRANSFORMER.  
M10236  
Fig. 11. Typical hookup of T7300D,F/Q7300A in two-stage heat and  
two-stage cool conventional system with two transformers.  
SUBBASE  
2
5
3
AS  
AS  
RC  
G
Y1  
Y2  
X
W2 W1 RH  
X4 X3 X1  
A1 A2 A3 C5  
C4  
C3  
C2  
C1  
T
T
COMPRESSOR  
CONTACTOR 1  
HEAT  
RELAY 2  
ECONOMIZER  
EQUIPMENT  
MONITOR 2  
DISCHARGE  
AIR  
SENSOR  
6
CA5  
CA4 CA3  
CA2 CA1  
T
T
FAN  
RELAY  
COMPRESSOR  
CONTACTOR 2  
EQUIPMENT  
MONITOR 1  
T7147 REMOTE COMFORT ADJUST MODULE  
GND  
1
4
HEAT  
RELAY 1  
L1  
HOT)  
L1  
(HOT)  
(
L2  
L2  
1
HEATING  
TRANSFORMER  
COOLING  
TRANSFORMER  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
JUMPER RC TERMINAL TO RH TERMINAL WHEN INSTALLED ON A SYSTEM WITH ONE TRANSFORMER.  
2
3
USE A1 AND A2 WHEN THE CONTACTS SHOULD BE NORMALLY CLOSED IN OCCUPIED MODE. USE A2 AND A3 WHEN  
THE CONTACTS SHOULD BE NORMALLY OPEN IN OCCUPIED MODE.  
4
5
CONNECT GND TO EARTH GROUND.  
INSTALL FIELD JUMPER BETWEEN X4 AND X TO POWER LEDS.  
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.  
6
M4945A  
Fig. 12. Typical hookup of T7300D,F/Q7300A in two-stage heat and  
two-stage cool conventional system with two transformers.  
5
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
SUBBASE  
5
3
AS  
AS  
X
Y1  
O
E
G
W2  
B
R
X4 X3  
X1 A1 A2  
C5  
C4  
C3  
C2  
C1  
T
T
T
FAN  
RELAY  
EQUIPMENT  
MONITOR 2  
DISCHARGE  
AIR  
SENSOR  
CA3 CA2 CA1  
CA5 CA4  
T
T7147 REMOTE COMFORT ADJUST MODULE  
GND  
HEAT  
RELAY 2  
COMPRESSOR  
CONTACTOR 1  
EQUIPMENT  
MONITOR 1  
EM. HT.  
RELAY  
4
ECONOMIZER  
2
COOL  
HEAT  
1
CHANGEOVER  
VALVE  
CHANGEOVER  
VALVE  
L1  
(HOT)  
L2  
TRANSFORMER  
1
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.  
USE A1 AND A2 WHEN THE CONTRACT SHOULD BE NORMALLY CLOSED IN OCCUPIED MODE.  
CONNECT GND TO EARTH GROUND.  
4
5
INSTALL FIELD JUMPER BETWEEN X4 AND X TO POWER LEDS.  
M4946A  
Fig. 13. Typical hookup of T7300E,F/Q7300C in two-stage heat and one-stage cool heat pump system.  
SUBBASE  
5
3
AS  
AS  
X
Y2  
Y1  
O
E
G
W1  
B
R
X4 X3  
X1 A1 A2 C5  
C4  
C3  
C2  
C1  
T
T
HEAT  
RELAY 3  
EQUIPMENT  
MONITOR 2  
COMPRESSOR  
CONTACTOR 2  
DISCHARGE  
AIR  
SENSOR  
FAN  
RELAY  
CA5  
CA4  
CA3  
CA2  
CA1  
T
T
COMPRESSOR  
CONTACTOR 1  
EQUIPMENT  
MONITOR 1  
T7147 REMOTE COMFORT ADJUST MODULE  
GND  
EM. HT.  
RELAY  
ECONOMIZER  
2
4
COOL  
HEAT  
1
CHANGEOVER  
VALVE  
CHANGEOVER  
VALVE  
L1  
(HOT)  
L2  
TRANSFORMER  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION INSTRUCTIONS.  
USE A1 AND A2 WHEN THE CONTACTS ARE NORMALLY CLOSE IN OCCUPIED MODE.  
CONNECT GND TO EARTH GROUND.  
3
4
5
INSTALL FIELD JUMPER BETWEEN X4 AND X POWER LEDS.  
M4947A  
Fig. 14. Typical hookup of T7300E,F/Q7300C in three-stage heat and two-stage cool heat pump system.  
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
SUBBASE  
X
L
2
Y
O
Y2  
E
3
G
W3  
W2  
B
R
X1  
X2  
EM.  
MODE  
COMPRESSOR  
CONTACTOR 2  
HEAT  
RELAY 2  
EQUIPMENT  
MONITOR 2  
COMPRESSOR  
CONTACTOR 1  
EM. HT.  
RELAY  
HEAT  
RELAY 3  
EQUIPMENT  
MONITOR 1  
COOL  
CHANGEOVER  
VALVE  
FAN  
RELAY  
HEAT  
CHANGEOVER  
VALVE  
1
L1  
(HOT)  
L2  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
EM. MODE IS ON CONTINUOUSLY IN EMERGENCY HEAT MODE.  
TRANSFORMER  
2
3
EM. HT. RELAY CYCLES IN EMERGENCY HEAT MODE.  
M4940A  
Fig. 15. Typical hookup of T7300E,F/Q7300C in three-stage heat and two-stage cool heat pump system.  
SUBBASE  
4
2
AS  
AS  
X
Y1  
G
Y2  
E
W3 W2 W1 R  
X4 X3 X1  
A1 A2 A3 C5 C4  
C3  
C2  
C1  
T
T
COMPRESSOR  
CONTACTOR 1  
EM. HT.  
RELAY  
HEAT  
RELAY 2  
ECONOMIZER  
5
EQUIPMENT  
MONITOR 2  
DISCHARGE  
AIR  
SENSOR  
CA5 CA4 CA3 CA2 CA1  
T
T
FAN  
RELAY  
T7147 REMOTE COMFORT ADJUST MODULE  
GND  
EQUIPMENT  
MONITOR 1  
HEAT  
RELAY 3  
1
3
COMPRESSOR  
CONTACTOR 2  
HEAT  
RELAY 1  
L1  
(
HOT)  
L2  
TRANSFORMER  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
USE A1 AND A2 WHEN THE CONTACTS SHOULD BE NORMALLY CLOSED IN OCCUPIED MODE. USE A2 AND A3 WHEN THE  
CONTACTS SHOULD BE NORMALLY OPEN IN OCCUPIED MODE.  
M4948A  
3
4
5
CONNECT GND TO EARTH GROUND.  
INSTALL FIELD JUMPER BETWEEN X4 AND X TO POWER LEDS.  
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.  
Fig. 16. Typical hookup of T7300E,F/Q7300D in three-stage heat and two-stage cool heat pump system.  
7
62-0135  
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Q7300A,C,D,G SERIES 2000 COMMERCIAL THERMOSTAT SUBBASES  
SUBBASE  
5
3
AS  
AS  
RC  
Y1  
G
Y2  
Y3  
X
W3 W2 W1 RH  
X4 X3 X1  
A1 A2 A3  
C5  
C4  
C3  
C2  
C1  
T
T
2
COMPRESSOR  
CONTACTOR 1  
HEAT  
RELAY 2  
COMPRESSOR  
CONTACTOR 2  
EQUIPMENT  
MONITOR 2  
ECONOMIZER  
6
DISCHARGE  
AIR  
SENSOR  
CA5  
CA4  
CA3  
CA2  
CA1  
T
T
FAN  
RELAY  
EQUIPMENT  
MONITOR 1  
T7147 REMOTE COMFORT ADJUST MODULE  
COMPRESSOR  
CONTACTOR 3  
GND  
HEAT  
RELAY 3  
1
4
HEAT  
RELAY 1  
L1  
(HOT)  
L1  
HOT)  
(
L2  
L2  
1
HEATING  
TRANSFORMER  
COOLING  
TRANSFORMER  
1
2
3
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.  
JUMPER RC TERMINAL TO RH TERMINAL WHEN INSTALLED ON A SYSTEM WITH ONE TRANSFORMER.  
USE A1 AND A2 WHEN THE CONTACTS SHOULD BE NORMALLY CLOSED IN OCCUPIED MODE. USE A2 AND A3 WHEN CONTACTS  
SHOULD BE NORMALLY OPEN IN OCCUPIED MODE.  
4
5
6
CONNECT GND TO EARTH GROUND.  
INSTALL FIELD JUMPER BETWEEN X4 AND X TO POWER LEDS.  
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.  
M4949A  
Fig. 17. Typical hookup of T7300D,F/Q7300G in three-stage heat and three-stage cool conventional system.  
A. ENGAGE TABS AT TOP OF THERMOSTAT AND SUBBASE OR WALLPLATE.  
Mounting Thermostat on Subbase  
Mount the thermostat on the subbase after the subbase is  
installed.  
³
Engage tabs at the top of the thermostat and  
subbase. Fig. 18.  
·
Press lower edge of case to latch.  
NOTE: To remove the thermostat from the wall,  
first pull out at the bottom of the thermo-  
stat; then remove the top.  
IMPORTANT  
Refer to the thermostat installation instructions for  
B. PRESS LOWER EDGE OF CASE TO LATCH.  
Installer Setup, Settings, Installer Self-Test and  
Troubleshooting information.  
M4824A  
Fig. 18 Mounting thermostat on subbase.  
Home and Building Control  
Home and Building Control  
Honeywell Inc.  
Honeywell Plaza  
P.O. Box 524  
Honeywell Limited-Honeywell Limitée  
155 Gordon Baker Road  
North York, Ontario  
Minneapolis, MN 55408-0524  
M2H 2C9  
62-0135 J.H. Rev. 12-96  
www.honeywell.com/building/components