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CT1800, CT1801, CT1802  
Electromechanical Fuel SaverThermostat and Wallplate/Subbase  
Installation Instructions  
CT1800 24V gas or oil heat, or 3 wire zone valves.  
CT1801 24V gas or oil heat/cool.  
CT1802 24V central electric heat/cool or single stage  
heat pump without auxiliary heat.  
Not for use on line voltage (120V) millivolt systems.  
Recycling Notice  
This control contains mercury in a sealed tube. Do not  
place control in the trash at the end of its useful life.  
Contact your local waste management authority for  
instructions regarding recycling and the proper disposal of  
this control, or of an old control containing mercury in a  
sealed tube.  
If this control is replacing a control that contains mercury in  
a sealed tube, do not place your old control in the trash.  
THERMOSTAT FEATURES  
I—Front of thermostat.  
LOW TEMPERATURE  
CONTROL LEVER (BLUE)  
HIGH TEMPERATURE  
CONTROL LEVER  
(RED)  
THERMOSTAT COVER  
THERMOMETER  
M9613  
II—Hinged cover lifted.  
III—Cover removed.  
2
4 HOUR PROGRAM DIAL  
HIGH  
TEMPERATURE  
CONTROL LEVER  
PROGRAM PINS  
FLIP-UP  
COVER  
AAA ALKALINE  
BATTERY (2) INCLUDED  
(
GRAY AREA FOR NIGHT  
LOW TEMPERATURE  
CONTROL LEVER  
SETTING)  
(RED)  
2
(
4 HOUR PROGRAM DIAL (BLUE)  
GRAY AREA FOR  
SWITCH  
NIGHT SETTINGS)  
BULBS  
CAPTIVE  
MOUNTING  
SCREW  
CAPTIVE  
HEAT  
MOUNTING  
SCREW  
ANTICIPATOR  
SETTING  
LEVER  
THERMOSTAT  
BASE  
PROGRAM  
INDEX WHEEL  
WALLPLATE (BEHIND  
THERMOSTAT. HELD  
ON BY TWO CAPTIVE  
SCREWS.)  
ADJUSTABLE HEAT  
ANTICIPATOR  
PROGRAM  
PIN SLOT  
PROGRAM  
INDEX WHEEL  
PROGRAM  
PIN  
TIME  
TIME INDICATOR  
ARROW  
INDICATOR  
ARROW  
STORAGE  
M9615  
THERMOSTAT COVER  
M9614  
D.F. • Rev. 11-96 • Printed in U.S.A.•  
M
• ©Honeywell Inc. 1996 • Form Number 69-0394—3  
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1
PREPARATION  
Check thermostat and wallplate suitability for your heating or heating/cooling system. Refer to Table 1.  
TABLE 1—THERMOSTAT AND SUBBASE APPLICATIONS.a  
Thermostat  
Model  
Subbase Wallplate  
Included  
For Use With  
CT1800  
199986B Wallplate  
2- or 3- wire, 150 to 30 volt control circuit. For gas or oil heating system or  
3-wire zone valve heating system.  
CT1801  
CT1802  
Q682A1079 Subbase 4- or 5- wire, 15-30 volt control circuit. For gas or oil heating/cooling system.  
Q682B1227 Subbase 4- wire, 15 to 30 volt control circuit. For single-stage heat pump without  
auxiliary heat or central electric heating/cooling systems that require the  
thermostat to control the fan in heating.  
a
Thermostat must be mounted on wallplate or subbase included in package to assure operation.  
If wallplate or subbase is mounted on a vertical  
Assemble tools as required.  
outlet box (check old installation), order 196393A  
Cover Plate and Adapter Ring (see appropriate illustration  
in Step 4). To order check your telephone directory for your  
local Honeywell distributor.  
FLAT BLADE  
SCREWDRIVER  
HAND OR POWER  
DRILL WITH 3/16 INCH  
DRILL BIT, IF NEEDED TO  
DRILL HOLES IN WALL  
Test to make certain that your heating and cooling  
systems are working. If either one does not work,  
contact your local heating/air conditioning dealer.  
NOTE: Do not operate cooling sytem if outdoor tempera-  
ture is below 50°F (10°C)  
MASKING TAPE, IF NEEDED  
TO LABEL WIRES  
DISCONNECTED FROM  
OLD THERMOSTAT  
WIRE CUTTER/STRIPPER OR SHARP  
KNIFE, IF NEEDED TO STRIP WIRES  
Turn off power to the heating/cooling system at the  
main fuse panel.  
LEVEL TO LEVEL THERMOSTAT  
FOR ACCURATE OPERATION  
M834A  
2
3
UNPACK THERMOSTAT  
THERMOSTAT  
COVER  
Remove and discard shipping wrap. Save package  
of screws, instructions and receipt.  
8
0
70  
60  
50  
Remove thermostat cover by lifting up from the  
bottom.  
LIFT  
COVER  
Carefully remove insert protecting switch bulbs.  
Loosen two captive mounting screws, and separate  
wallplate or subbase from back of thermostat base.  
CAPTIVE  
MOUNTING  
SCREWS  
THERMOSTAT  
BASE  
M9617  
REMOVE OLD THERMOSTAT  
recognize the heat anticipator.) Make a note here  
Remove cover of old thermostat. If the cover does  
not snap off when pulled firmly from the bottom,  
of that anticipator setting for future reference. If your  
thermostat does not have a heat anticipator, do not be  
concerned. Move on to next paragraph.  
check for a screw that locks on the cover.  
Before removing the old thermostat from the wall,  
look at it carefully to locate the heat anticipator  
adjustment mechanism. (See illustration to help you  
Loosen screws holding thermostat to wallplate,  
subbase or wall and lift away.  
69-0394—3  
2
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IMPORTANT: If old thermostat has B or O terminals, this  
thermostat cannot be used on your system.  
EXCEPTION: The CT1802 Thermostat can be used  
on a system with B or O terminals.  
BULB  
SWITCH  
One or two extra wires?  
If you are replacing a Honeywell Chronotherm Thermostat,  
ANTICIPATOR  
SCALE  
®
you may find one or two wires that go to the clock termi-  
®
nals on the Chrontherm Thermostat wiring wallplate. Do  
ANTICIPATOR  
SETTING LEVER  
not allow them to touch, or you may damage your trans-  
former. Disconnect the wires, and wrap them separately,  
using electrical tape. Do not wrap them together. Place  
the wires where they will not interfere with the operation of  
the new thermostat. Record the colors and terminal  
designation labels of the remaining wires.  
M6115  
Disconnect wires from old thermostat, wallplate or  
subbase. Tape each end and label with the letter of  
the terminal designation to make reconnection easier. If  
there are only two wires labeling is not necessary.  
4
MOUNT WALLPLATE OR SUBBASE  
EXISTING  
EXISTING  
HORIZONTAL  
OUTLET BOX  
HORIZONTAL  
OUTLET BOX  
O
R
B
R
W
W
HEATING/  
COOLING  
SUBBASE  
HEATING-ONLY  
WALLPLATE  
G
Y
FAN  
OFF COOL  
ON  
AUTO  
HEAT  
M856A  
M1553A  
If mounting on outlet box , mount as shown in  
appropriate illustration.  
Position wallplate or subbase as shown in appropriate  
figure, and loosely insert the screws supplied.  
When mounting on wall, hold wallplate or subbase in  
position and mark holes on wall. Use level to make  
Carefully level the wallplate or subbase and firmly  
tighten screws.  
sure wallplate or subbase will be level. Drill 3/16 in. holes  
and gently tap anchors into holes until flush with the wall.  
VERTICAL  
OUTLET  
BOX  
1
96393A  
ASSEMBLY  
COVER  
PLATE  
3
SCREW HOLES  
ADAPTER  
RING  
WITH PLASTIC  
ANCHORS  
MOUNTING  
SCREWS (2)  
O
O
B
B
W
R
R
G
W
G
Y
Y
SUBBASE OR  
WALLPLATE  
FAN  
OFF COOL  
ON  
AUTO  
HEAT  
M866  
MOUNTING  
SCREWS (2)  
HEATING/COOLING SUBBASE  
M1552A  
3
69-0394—3  
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3
SCREW HOLES  
WITH PLASTIC  
ANCHORS  
SPIRIT LEVEL  
O
HEATING-ONLY  
WALLPLATE  
B
R
G
W
Y
FAN  
OFF COOL  
ON  
AUTO  
HEAT  
M2419  
M9612  
5
WIRE WALLPLATE OR SUBBASE  
NOTE: All wiring must comply with local electrical codes  
and ordinances.  
3-WIRE SYSTEM  
Refer to illustration and strip thermostat wire  
insulations as necessary.  
R
FOR STRAIGHT  
CONNECTION—  
STRIP 5/16 in. [8 mm]  
W
FOR WRAPAROUND  
CONNECTION—  
STRIP 7/16 in. [11 mm]  
BARRIER  
B
W
HEATING  
VALVE OR  
MOTOR  
1
L2  
L1  
M1556B  
(HOT)  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
FOR CT1800 heating—only  
M2485B  
For 2-wire system, connect either wire to R terminal  
and the other wire to W terminal. For 3-wire system,  
connect W wire to W terminal, R wire to R terminal, and  
remaining wire to B terminal. Firmly tighten screws.  
FOR CT1801 heating/cooling  
Connect the wires to matching terminals on the  
subbase.  
Push excess wire back into wall, and plug hole in  
wall with nonflammable insulation to prevent drafts  
from affecting thermostat operation.  
NOTE: If there are four wires, connect wire marked R to  
terminal RH and add a jumper wire to connect to RC. If  
RC is left unconnected, the air conditioner will not turn  
on. The 4-wire drawing on page shows how to jumper  
RC to RH. Strip the insulation off the wire where it  
connects to the terminals. Firmly tighten screws.  
2-WIRE SYSTEM  
If the labels do not agree with the terminal designations on  
your new subbase:  
R
Refer to Table 2  
Determine correct hookup from the listed control  
function and the equipment control circuit.  
W
Push excess wire back into wall, and plug hole in the  
wall with nonflammable insulation to prevents drafts  
from affecting thermostat operation.  
HEATING RELAY  
OR VALVE COIL  
1
L2  
L1  
(
HOT)  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M2484B  
69-0394—3  
4
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4-WIRE SYSTEM  
5-WIRE SYSTEM  
2
RC  
RH  
RC  
RH  
W
W
G
G
Y
Y
FAN  
ON  
COOL  
AUTO  
HEAT  
OFF  
FAN  
ON  
COOL  
AUTO  
HEAT  
OFF  
HEATING  
RELAY OR  
VALVE COIL  
FAN  
RELAY  
COOLING  
CONTACTOR  
COIL  
HEATING  
RELAY OR  
VALVE COIL  
FAN  
RELAY  
COOLING  
CONTACTOR  
COIL  
1
1
1
L1  
L1  
L1  
HOT)  
(
HOT)  
(
(HOT)  
L2  
L2  
L2  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
M2413  
M2414  
2
INSTALL JUMPER BETWEEN RC AND RH.  
TABLE 2—TERMINAL DESIGNATIONS.  
Subbase Terminal  
Control Function  
R or RH  
Heating transformer power to control circuit  
RX  
W
Y
Cooling transformer power to control circuit  
Heating relay or valve  
Cooling relay  
G
B
Fan relay  
Heating changeover valve or damper control circuit  
Cooling changeover valve or damper control circuit  
Heat pump compressor control circuit.  
O
P
FOR CT1802 heating/cooling  
SINGLE STAGE HEAT PUMP  
WITHOUT AUXILIARY HEAT) SYSTEM  
(
Connect the wires to matching terminals on the  
subbase. Firmly tighten screws.  
Push excess wire back into wall, and plug hole in  
wall with nonflammable insulation to prevent drafts  
from affecting thermostat operation.  
3
W
B
Y
2
P
R
O
CENTRAL ELECTRIC SYSTEM  
G
FAN  
COOL  
ON  
AUTO  
HEAT  
OFF  
W
B
Y
FAN  
RELAY  
COMPRESSOR  
CONTACTOR  
COIL  
REVERSING  
VALVE  
P
R
O
L2  
G
L1  
FAN  
COOL  
(HOT)  
ON  
AUTO  
HEAT  
OFF  
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
COOLING  
CONTACTOR  
COIL  
FAN  
RELAY  
HEATING  
RELAY OR  
VALVE COIL  
IF COMPRESSOR IS CONNECTED TO OLD THERMOSTAT'S  
"Y" TERMINAL WITH A JUMPER TO "W", USE NEW THERMOSTAT'S  
P" TERMINAL FOR COMPRESSOR. IF OLD THERMOSTAT HAS  
"
1
ONE WIRE TO "Y" AND ONE TO "W", USE "Y" AND "W" ON NEW  
THERMOSTAT; DO NOT USE "P". IMPORTANT– IF OLD  
THERMOSTAT USES A W2 (AUXILIARY OR EMERGENCY HEAT)  
TERMINAL, THIS THERMOSTAT MAY NOT BE USED. THIS  
THERMOSTAT IS NOT DESIGNED TO CONTROL AUXILIARY HEAT.  
L2  
L1  
(
HOT)  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND  
OVERLOAD PROTECTION AS REQUIRED.  
3
SOME HEAT PUMPS USE "B" INSTEAD OF "O".  
M2415B  
M2412A  
5
69-0394—3  
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6
MOUNT THE THERMOSTAT  
Note the tabs on the top inside edge of the thermostat  
base. These fit the slots molded into the top of the  
wallplate or subbase.  
Hang the thermostat base on the wallplate or  
subbase as shown in illustration.  
TAB (2)  
Insert the two captive mounting screws located in  
the bottom corners of the thermostat base (see  
illustration); firmly tighten.  
MOUNTING SLOT (2)  
1
IMPORTANT: Do not cycle heating system until step 7 is  
completed.  
35  
3
0
2
5
2
0
1
0
JUMPER WIRES  
THERMOSTAT  
BASE  
WALLPLATE  
OR SUBBASE  
CAPTIVE  
MOUNTING SCREWS  
M3408  
7
SET HEAT ANTICIPATOR LEVER  
The thermostat adjustable heat anticipator must be  
correctly set to accurately control the on-time length  
valve, a relay or burner control box, Aquastat controller or  
zone valve with the thermostat wires connected to it.These  
controls are usually located behind the furnace cover. See  
next illustration.  
of the system. An incorrect setting can result in room  
temperature swings or burn out the anticipator and void the  
thermostat warranty.  
If current rating is still unavailable, proceed as follows:  
Connect the probes of an ac ammeter (0 to 2.0A for  
example) between the R (or RH) and W terminals on  
the wallplate or subbase.  
Let the system operate through the ammeter for at least  
one minute before taking reading. Record the reading  
Make sure you have the current draw (anticipator setting)  
for your system. This is the number you wrote in the box in  
Step 3. If you were unable to find the current draw for Step 3,  
this information can be found printed on the primary control  
at the furnace or boiler. The primary control is usually a gas  
here  
.
OIL BURNER CONTROL  
SHOWS  
CURRENT  
DRAW  
SHOWS  
VOLTAGE  
RATING  
SHOWS  
VOLTAGE  
30 VACRATING  
V8043E 1004 4  
0.2 AMP  
2
4V 50/60CY  
SHOWS  
ANTICIPATOR  
SETTING  
.32 AMP @ 60CY  
SHOWS  
VOLTAGE  
RATING  
T
T
TO  
BURNER  
F
F
24 Vac 50/60 Hz  
0.4 AMP  
FROM MAIN  
SHOWS  
FUEL SUPPLY  
ANTICIPATOR  
SETTING  
ZONE VALVE  
M6116B  
TYPICAL GAS VALVE  
Move the heat anticipator to match the number you  
recorded in Step 3 or found on the primary control  
as shown above, or as recorded in Step 7.  
IMPORTANT: Most hot water systems require a setting of  
1.3 times the valve current rating.  
ANTICIPATOR  
SCALEPLATE  
ANTICIPATOR  
SETTING LEVER  
M9616  
69-0394—3  
6
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8
INSTALL CLOCK BATTERIES  
BATTERY LOCATION  
FOR (2) AAA BATTERIES;  
INSTALL WITH POSITIVE  
ENDS UP  
Power is supplied to the clock by two AAA alkaline  
batteries (included). Install clock batteries in  
thermostat as shown. Once a year, or when batteries are  
dead, replace with two new AAA alkaline batteries. We  
recommend Energizer batteries. Other types of batteries  
®
are more likely to leak, which could damage the clock. The  
thermostat itself will operate without batteries, but will not  
operate as a fuel saver.  
M9619  
9
SET CLOCK  
Adjust the clock by moving the minute hand in  
PROGRAM  
INDEX  
WHEEL  
clockwise direction. Do not reverse the minute hand.  
When time is correctly set, the Time Indicator Arrow  
(see illustration) must point to the correct time and  
the corresponding daytime (light) or nighttime (dark)  
portion of the program dial.  
TIME  
INDICATOR  
ARROW  
M2499  
10 ATTACH THERMOSTAT COVER  
Make sure the packing inserts in the thermostat  
base have been removed, as explained in Step 2.  
Place the two tabs on upper edges of cover into the  
mounting slots in the thermostat base.  
Swing cover downward until it engages catch at  
bottom of base.  
M9618  
11  
CHECKOUTTHERMOSTAT OPERATION AND SETTEMPERATURE CONTROL LEVERS  
The two levers on top of the thermostat control the  
low and high temperature for energy savings and  
comfort control as shown in the illustration.  
CAUTION  
Do not check operation by shorting across  
terminals of relay or valve coil; this will burn out the  
thermostat heat anticipator, which will void the  
warranty.  
LOW TEMPERATURE  
BLUE MARK)  
SET LEVER  
HIGH TEMPERATURE  
(RED MARK)  
SET LEVER  
(
50  
60 70  
80  
Heating-Only System  
Turn on power to the furnace.  
M859  
7
69-0394—3  
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Push both temperature control levers together at  
least 5°F (3°C) above room temperature.The heat  
should come on. The fan will start when the furnace heats  
up,  
Move both levers together 5°F (3°C) above room  
temperature.The cooling equipment should shut off.  
Place the fan switch at ON.The fan should run  
continuously with the system in any position.  
Move both levers 5°F (3°C) below room temperature.  
The heat should shut off.  
Place the system switch at OFF. Move both  
temperature levers to various positions. The heating  
and cooling systems should not operate.  
Operate the entire heating system for at least one  
complete cycle.  
Operate the entire system for at least one complete  
cycle with the system switch at COOL and one  
complete cycle with the switch at HEAT.  
IMPORTANT: If thermostat fails any test, refer to the  
Troubleshooting Guide in Owner’s manual.  
IMPORTANT: If thermostat fails any test, refer to trouble-  
Heating/Cooling System  
shooting guide in owner’s manual.  
Turn on power to the furnace and cooling system.  
After checkout, reset both temperature levers to  
desired temperatures.  
Place the system switch lever at HEAT and the fan  
switch lever at AUTO.  
For heating season:  
Push both temperature control levers together at  
least 5°F (3°C) above room temperature.The heat  
should come on. The fan will start when the furnace heats  
up. On the CT1802, the fan will start immediately.  
Move the blue lever to the energy savings  
temperature you want when you are sleeping or your  
home is not occupied.  
Set the red lever to the temperature you want for  
normal comfort periods.  
Move both levers together at 5°F (3°C) below room  
temperature.The heat should shut off.The fan will  
stop when the furnace cools.  
For cooling season:  
IMPORTANT: To avoid compressor damage, do not  
operate the cooling system if outdoor temperature is  
below 50°F (3°C) below room temperature.The heat  
should shut off. The fan will stop when the furnace  
cools.  
Move the red lever to the energy savings  
temperature you want when you are sleeping or your  
home is not occupied.  
Set the blue lever to the temperature you want for  
normal comfort periods.  
Place the system switch level at COOL and the fan  
switch lever at AUTO.  
Refer to the owner’s manual form 69-0333 for operating  
and programming instructions.  
Push both temperature control levers together at  
least 5°F (3°C) below room temperature.The cooling  
equipment should operate, and the fan will start. Allow for  
any time delay that may be built into the compressor  
control circuit.  
If you have questions regarding the thermostat please If you have questions regarding the Honeywell Fuel Saver  
Thermostat please visit our web site at www.honeywell.com/yourhome, or call the customer information line at  
1-800-468-1502.  
Helping You Control Your World  
www.honeywell.com/yourhome