Honeywell CT70 Thermostat User Manual

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CT70  
Heat Pump  
Thermostat Wiring Guide  
2
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HOW TO USE THIS GUIDE  
Before you disconnect the wires and remove your  
existing thermostat, be sure this new thermostat, see the  
CT70 wiring hookup diagram, will replace it and that you  
understand how you will reconnect the wiring. To do that,  
proceed as follows:  
Step 1  
Find the manufacturer of your heat pump in the Table of  
Contents, and turn to the appropriate page.  
Step 2  
Expose the wiring on your existing thermostat (the  
subbase) and check that the terminals on your existing  
thermostat coincide with the terminals shown in the  
second column (Existing thermostat wiring).  
If they do, read and follow the installation instructions  
provided with the thermostat.  
If they do not, call Honeywell Customer Assistance toll  
free at 1-800-468-1502, Monday-Friday, 7:00 a.m. - 5:30  
p.m. Central time, to be sure you can safely use this  
thermostat to control your heat pump.  
Before you call, please have the following information  
available: thermostat model number and date code, heat  
pump model number and manufacturer, and number of  
wires connected to the thermostat. The date code is  
usually stamped on the back of the thermostat and is a  
four-digit number; for example, 9346.  
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TABLE OF CONTENTS  
How to Use This Guide ................................................. 3  
Heat Pumps are Different.............................................. 6  
Heat Pumps are Two Systems in One .......................... 7  
Definitions of Terminal Functions ............................... 8,9  
Heat Pump Manufacturers ..................................... 11-22  
Amana....................................................................11  
American Standard................................................ 20  
Arcoaire................................................................. 13  
Bard....................................................................... 12  
Borg Warner..................................................... 21,22  
B.D.P. (Bryant-Day/Night-Payne).......................... 14  
Carrier ................................................................... 15  
Comfortmaker ....................................................... 13  
Friedrich ................................................................ 16  
Heil Quaker ........................................................... 17  
Janitrol................................................................... 12  
Lennox .................................................................. 18  
Luxaire (Moncrief, Fraser, Johnston) .................... 21  
Rheem................................................................... 19  
Ruud...................................................................... 19  
Snyder General..................................................... 13  
Tappan .................................................................. 12  
Tempstar ............................................................... 17  
Trane..................................................................... 20  
Whirlpool ............................................................... 17  
Williamson............................................................. 12  
York .................................................................. 21,22  
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HEAT PUMPS ARE DIFFERENT  
Heat pump systems  
usually have a  
supplemental,  
Second Stage  
heating system that  
operates only when  
necessary. This  
heat pump  
thermostat is  
designed to  
minimize more  
expensive second-  
stage operation,  
indicated by the  
green AUX. HEAT  
light on your  
thermostat.  
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HEAT PUMPS ARE TWO SYSTEMS IN ONE  
MILD WEATHER  
OUTDOORS  
INDOORS  
AUXILIARY  
HEATING  
ELEMENT  
OFF  
OUTDOOR  
AIR  
INDOOR  
AIR  
HEAT  
TRANSFER  
M9069  
In mild weather, virtually all of the demand for heat in  
buildings can be met by the heat pump compressor. This  
First Stage process of moving heat indoors is very  
economical. As the air becomes colder outside, the first  
stage may be unable to deliver enough heat to maintain the  
desired comfort level in the building.  
SEVERE WEATHER  
OUTDOORS  
INDOORS  
AUXILIARY  
HEATING  
ELEMENT  
ON  
OUTDOOR  
AIR  
INDOOR  
AIR  
HEAT  
TRANSFER  
M9078  
During high heat demand, the thermostat will call for  
additional Second Stage power from the auxiliary heat  
system. This auxiliary heat is commonly electric resistance  
heat and is two to three times more expensive to operate  
than the compressor. If you have specific questions  
concerning the operation of your heat pump, please contact  
the equipment manufacturer.  
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DEFINITIONS OF TERMINAL FUNCTIONS  
Each terminal of the CT70 controls a different heat pump  
function. Here is a list of the possible heat pump  
functions:  
Function  
Definition  
FIRST STG. HEAT:  
When this terminal is activated, the heat  
pump is on and heating the living space.  
AUXILIARY HEAT:  
When this terminal is activated, the  
auxiliary heating source is on because the  
heat pump is unable to meet the heating  
demand of the living space.  
FIRST STG. COOL:  
COMPRESSOR:  
When this terminal is activated, the heat  
pump is on and cooling the living space.  
When this terminal is activated, the heat  
pump is on and either heating or cooling  
the living space, depending on the system  
switch position.  
C/O VALVE HEAT:  
C/O VALVE COOL:  
EM. HEAT:  
Heating Changeover Valve. This terminal  
is activated when the system switch is in  
the HEAT position. It provides changeover  
in heat pumps that change over in  
heating.  
Cooling Changeover Valve. This terminal  
is activated when the system switch is in  
the COOL position. It provides  
changeover in heat pumps that change  
over in cooling.  
Emergency Heat. This terminal is  
activated when the system switch is in the  
EM. HT position. In this situation, the heat  
pump is not activated.  
8
FAN:  
When this terminal is activated, the fan is  
on. With the fan switch in the auto  
position, the fan cycles on and off with the  
heat pump. With the fan switch in the ON  
position, the fan is  
on continuously.  
MULTIPLE AUX.  
HEAT LOADS:  
This terminal is activated when additional  
auxiliary heat loads are required. Because  
the CT70 only has provisions for one  
auxiliary heat load, these loads must be  
connected to the AUXILIARY HEAT  
terminal.  
OUTDOOR  
SENSOR:  
This terminal is not connected to the  
CT70. On your original thermostat, this  
terminal was activated by an outdoor  
sensor that controlled the auxiliary heat  
source.  
OUTDOOR STAT:  
Outdoor Thermostat. This terminal is  
activated when the system switch is in the  
EM. HT. position. The outdoor thermostat  
controls the amount of auxiliary heat that  
is activated.  
POWER:  
This terminal connects to the power side  
of the 24-volt transformer.  
COMMON:  
This terminal connects to the common  
side of the 24-volt transformer.  
SYSTEM MONITOR: Some heat pumps have the ability to  
indicate when the heat pump is  
malfunctioning. When this occurs, this  
terminal is activated and the EM. HT. LED  
is activated.  
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L1  
HOT) L2  
(
1
CHANGEOVER  
RELAY (COOL)  
AUX. HEAT  
RELAY  
SYSTEM  
MONITOR  
FAN RELAY  
CHANGEOVER  
RELAY (HEAT)  
4
X
L
B
W2  
3
2
W1  
E
R
G
O
Y1  
EM. HEAT  
RELAY  
HEAT RELAY 1  
COMPRESSOR  
CONTACTOR  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
2
3
REMOVE W1-Y1 JUMPER WHEN HEAT RELAY 1 IS USED.  
WHEN L TERMINAL IS CONNECTED TO SYSTEM MONITOR, EM. HEAT. LED  
ALSO INDICATES COMPRESSOR MALFUNCTION.  
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X TERMINAL MUST BE CONNECTED FOR PROPER OPERATION.  
M8504  
Typical wiring hookup of CT70 with jumper intact.  
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AMANA  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
2
COMMON  
POWER  
X1 or  
or RC or RH  
Y or Y1  
C
X
1
R
R
COMPRESSOR  
Y1  
3
1
ST STG.  
W1  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
G
W2  
G
C/O VALVE  
HEAT  
B
or  
W
B
C/O VALVE  
COOL  
O
E
O
E
L
EM. HEAT  
SYSTEM  
MONITOR  
Jumper these two terminals if both are present  
This terminal must be connected to transformer common.  
Remove this factory-installed jumper for independent stage 1  
heat and cool connection.  
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BARD/JANITROL/TAPPAN/WILLIAMSON  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
C
or X1 or  
X
R
X
RHor RC or  
Y
R
COMPRESSOR  
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
G
W2  
G
C/O VALVE  
HEAT  
4
B
4
or W1  
B
O
L
C/O VALVE  
COOL  
O
L
SYSTEM  
MONITOR  
EM. HEAT  
E
E
MULTIPLE AUX.  
HEAT LOADS  
W3  
3
3
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
Connect multiple second stage heating loads to W2 terminals.  
Thermostat is connected to either O or B terminal, but not  
both.  
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ARCOAIRE/SNYDER GENERAL/COMFORTMAKER  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
X,X1 or  
C
X
R
Y
R
COMPRESSOR  
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W2 or W1  
G
W2  
G
C/O VALVE  
HEAT  
B
O
C/O VALVE  
COOL  
O
SYSTEM  
MONITOR  
L
or  
E
X
L
E
EM. HEAT  
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
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B.D.P. (BRYANT-DAY/NIGHT-PAYNE)  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
C1 or X1 or  
R
C
X
R
COMPRESSOR  
W1 or  
Y
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
W2  
G
G
B
C/O VALVE  
HEAT  
B
3
C/O VALVE  
COOL  
Y1 or  
O
O
SYSTEM  
MONITOR  
L
X
or  
or  
F
E
L
E
EM. HEAT  
MULTIPLE AUX.  
HEAT LOADS  
3
W3  
P
DEFROST  
P
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
Connect multiple second stage heating loads to W2 terminals.  
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CARRIER  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
C
X
R
R
Y
COMPRESSOR  
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W1 or W2  
G
W2  
G
C/O VALVE  
HEAT  
B
O
C/O VALVE  
COOL  
O
SYSTEM  
MONITOR  
F
or  
E
L
L
E
EM. HEAT  
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
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FRIEDRICH  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
X
or  
C
or X1  
X
RH or RC  
R
COMPRESSOR  
Y2 or  
W1  
Y
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
G
W2  
G
C/O VALVE  
HEAT  
B
B
C/O VALVE  
COOL  
O
E
or Y1  
L
O
SYSTEM  
MONITOR  
L
EM. HEAT  
or X2  
E
W3 or  
U
3
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
Tape off the end of the wire. Jumper is not required on this  
thermostat (CT70).  
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HEIL QUAKER/WHIRLPOOL/TEMPSTAR  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
COMMON  
POWER  
C
or  
R
B
X
R
COMPRESSOR  
Y
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W
G
W2  
G
C/O VALVE  
HEAT  
B
O
B
O
C/O VALVE  
COOL  
SYSTEM  
MONITOR  
L
E
EM. HEAT  
X
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
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LENNOX  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
COMMON  
POWER  
Y
or  
X
X
BL or V/VR  
R
1
ST STG.  
HEAT (COMP)  
R
or  
M
W1  
1
ST STG.  
COOL  
Y1  
2
2
ND STG.  
HEAT  
O
Y
or  
or  
Y
F
W2  
FAN  
G
B
C/O VALVE  
HEAT  
C/O VALVE  
COOL  
BK or  
R
O
SYSTEM  
MONITOR  
L
E
EM. HEAT  
E
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
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RHEEM/RUUD  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
X
X
R
Y
R
COMPRESSOR  
Y1  
2
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
G
W2  
G
C/O VALVE  
HEAT  
B
O
B
O
C/O VALVE  
COOL  
SYSTEM  
MONITOR  
L
E
L
E
EM. HEAT  
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
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TRANE/AMERICAN STANDARD  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
1
COMMON  
POWER  
B
X
R
R
W1  
2
1
ST STG.  
HEAT  
Y
Y1  
W2  
G
W1 or  
W
AUX. HEAT  
FAN  
G
C/O VALVE  
HEAT  
B
C/O VALVE  
COOL  
O
O
L
SYSTEM  
MONITOR  
F
or  
T
L
OUTDOOR  
SENSOR  
3
OUTDOOR  
STAT  
W2 or X2  
E
This terminal must be connected to transformer common.  
Leave factory-installed jumper in place.  
Tape off end. CT70 replaces outdoor reset with improved zero  
droop performance.  
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YORK/BORG WARNER/LUXAIRE (MONCRIEF, FRASER-JOHNSTON)  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
COMMON  
POWER  
X
or  
R
Y
B
X
R
COMPRESSOR  
Y1  
3
1
ST STG.  
W1  
HEAT  
AUX. HEAT  
FAN  
W
or W2  
G
W2  
G
C/O VALVE  
HEAT  
H
O
B
O
L
C/O VALVE  
COOL  
4
SYSTEM  
MONITOR  
X
or  
E
L
4
EM. HEAT  
E
2
4
MULTIPLE AUX.  
HEAT LOADS  
W3  
This terminal must be connected to transformer common.  
Connect multiple second stage heating loads to W2 terminals.  
Leave factory-installed jumper in place.  
If present on original equipment.  
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YORK/BORG WARNER  
Wiring  
terminal  
function  
Existing  
thermostat  
wiring  
New  
thermostat  
wiring  
1
COMMON  
POWER  
B
or X2  
R
X
R
1
ST STG.  
W1  
W1  
HEAT  
AUX. HEAT  
FAN  
W2  
G
W2  
G
1
ST STG.  
COOL  
2
Y1  
Y1  
C/O VALVE  
HEAT  
B
O
C/O VALVE  
COOL  
SYSTEM  
MONITOR  
L
E
EM. HEAT  
E
This terminal must be connected to transformer common.  
Remove factory-installed jumper.  
22  
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Automation and Control Solutions  
Honeywell International Inc.  
1985 Douglas Drive North  
Golden Valley, MN 55422  
69-0866—2 C.H. Rev. 01-95 www.honeywell.com/yourhome  

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