Honeywell CT41A User manual

® U.S. Registered Trademark

INSTALLATION INSTRUCTIONS

69-0788-2

CT41A

Heating/Cooling Thermostat

Heating/Cooling

15 to 30 Vac Thermostat

Congratulations on the purchase of your new thermostat!

YOUR NEW CT41A THERMOSTAT

Your new CT41A Thermostat replaces most 15 to 30V,

4-wire, heating/cooling system thermostats. The CT41A

is suitable for gas or oil heat or electric air conditioning

systems.

Direct questions about this thermostat to our Web site at

www.honeywell.com/yourhome or call the customer

information line at 1-800-468-1502.

MERCURY NOTICE

If this control is replacing a control that contains

mercury in a sealed tube, do not place your old

control in the trash. Dispose of it properly.

Contact your local waste management authority

for instructions regarding recycling and the

proper disposal of an old control.

1 PREPARE FOR INSTALLATION

If you are unsure about wiring procedures, please call a

qualified service technician for assistance.

❑To correctly install your new thermostat, follow these

step-by-step instructions. It is recommended that, as

you read, understand, and complete each step, you

place a check mark in each box provided.

❑See Your New CT41A Thermostat section above to

determine the thermostat suitability for compatibility

with your home system. If not, return it to the retailer.

Acquire the required installation tools and supplies, as

needed. See Fig. 1.

Fig. 1. Required installation tools/supplies.

M10614

MERCUR

SWITCH

YPICAL LOCATION OF A MERCURY

WITCH IN A THERMOSTAT

M20551

SCREWDRIVER HAND OR POWER

DRILL WITH 3/16 INCH

DRILL BIT, IF NEEDED TO

DRILL HOLES IN WALL

WIRE CUTTER/STRIPPER IF NEEDED TO STRIP WIRES

LEVEL, IF NEEDED TO LEVEL

THERMOSTAT FOR APPEARANCE

CT41A HEATING/COOLING THERMOSTAT

69-0788-2 2

2 REMOVE OLD THERMOSTAT

❑Test to be sure your heating and air conditioning

systems (where applicable) are working correctly. If

not, contact your local heating/air conditioning dealer.

To avoid compressor damage, do not operate the

cooling system when outdoor temperature is below

50°F (10°C).

CAUTION

Equipment Damage Hazard.

Handling wires during installation can

damage equipment.

Disconnect power at furnace or main breaker/

fuse box before beginning installation.

❑Carefully unpack your new thermostat and save the

package of screws, the instructions and the receipt.

❑Remove the cover from the old thermostat. If it does

not snap off when pulled firmly from the bottom, 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 Fig. 2. Make a note here ________

of the anticipator setting for future reference. The heat

anticipator pointer, if adjustable, is set at one of a

series of numbers representing the (electrical) current

rating of the primary control of your system (in

amperes). The numbers range from 0.18 to 1.0. If no

heat anticipator/indication is showing, do not be

concerned; move on to the next step.

Fig. 2. Locating heat anticipator adjustment

mechanism.

❑Loosen screws holding thermostat to subbase,

wallplate or wall and lift away.

❑Disconnect wires from old thermostat or subbase. As

you disconnect each wire, tape the end and label it

with the letter of the terminal designation. If there are

only two wires, they do not require labeling. Wrap

wires around a pencil to keep them from falling back

into the wall as shown in Fig. 3.

Fig. 3. Wrapping wires around pencil.

❑Keep the old thermostat for reference until your new

thermostat is functioning smoothly.

3 WIRE AND MOUNT THERMOSTAT

❑Connect wires from the wall to the matching terminals

on the back of the thermostat. See Fig. 4. Tighten the

screws.

NOTE: If terminal designations on old thermostat do not

match those on new thermostat, see Table 1.

Fig. 4. Connect wires from wall to thermostat

matching terminals.

.18

.25

BOTTOM

MOUNTING HOLE

M3782A

TEMPERATURE

SETTING LEVER

MOUNTING CLIPS

(FOR COVER)

TOP MOUNTING HOLE

(THERMOSTAT TO WALL

OR OUTLET BOX)

ADJUSTABLE HEAT

ANTICIPATOR

SETTING LEVER

FAN SWITCH

SYSTEM SWITCH

Table 1. Terminal Functions.

Old Thermostat

Terminal Marking Function

New

Thermostat

Terminal

Marking

G or F Fan G

Y or C or M or Y1Cooling Y

W or H or W1Heating W

RC, V, VC or B Power Your 5-wire

system cannot

use this

thermostat;

use a CT87B

instead.

RH, M, VR, 4, A or

Power R

WIRES THROUG

WALL OPENING

M5136

TERMINAL SCREWS

M8067A

CT41A HEATING/COOLING THERMOSTAT

369-0788-2

❑Push excess wire back into wall and plug hole with

nonflammable insulation to prevent drafts from

affecting thermostat operation.

❑Remove thermostat cover by pulling outward on right

edge of cover until it snaps free of the thermostat

base.

❑Fasten thermostat to wall or vertical outlet box with a

screw through the top mounting hole. See Fig. 2 for

hole location.

❑Place a bubble level or plumb line against the

thermostat to find the level position. See Fig. 5. Start a

screw in the center of the bottom mounting hole.

(Move the temperature setting lever, if necessary, to

uncover the mounting hole.)

Fig. 5. Level thermostat.

❑Recheck for level positioning and firmly tighten both

mounting screws.

❑Be sure you have the current draw anticipator setting

for your system. This is the number you wrote in the

box in step 2 Remove Old Thermostat section. If you

could not find the current draw for step 2, look on your

primary control at the furnace. See Fig. 6. (The

primary control is usually a gas valve, zone valve, or a

relay or burner control box with the thermostat wires

connected to it. For electric heat, add the fan relay

current, usually 0.2A to 0.4A.)

Fig. 6. Locate your system current draw anticipator

setting.

❑Set the heat anticipator indicator at the rating printed

on the primary control. See Fig. 7.

CAUTION

Heat Anticipator Hazard.

Setting heat anticipator too low can cause

anticipator burnout.

Set heat anticipator at recommended rating to

avoid shorting out your valve or control and

prevent burnout of your heat anticipator.

Fig. 7. Set heat anticipator indicator to match your

primary control rating.

❑Press thermostat cover firmly onto the mounting clips.

See Fig. 2.

M3774

.18

.25

BUBBLE LEVEL

PLUMB

LINE

PLUMB

BOB OR

WEIGH

V8043E 1004 4

24V 50/60CY

.32 AMP @ 60CY

8406

24 Vac 50/60 Hz

0.4 AMP

30 VAC

0.2 AMP

OIL BURNER CONTROL

SHOWS

CURRENT

DRAW SHOWS

VOLTAGE

RATING

M6116B

ROM MAIN

UEL SUPPLY

SHOWS

VOLTAGE

RATING TO

BURNER

SHOWS

ANTICIPATOR

SETTING

TYPICAL GAS VALVE

ZONE VALVE

SHOWS

VOLTAGE

RATING

SHOWS

ANTICIPATOR

SETTING

.18

.25

SCALEPLATE

M378

ADJUSTABLE

HEAT

ANTICIPATOR

SETTING LEVE

CT41A HEATING/COOLING THERMOSTAT

69-0788-2 4

4 CHECK OUT THERMOSTAT

The System switch controls as follows:

Heat: heating system only operates.

Off: heating and air conditioning systems are discon-

nected.

Cool: air conditioning system only operates.

The Fan switch controls as follows:

Auto: fan operates when heating or air conditioning

system operates.

On: fan operates continuously.

NOTE: In the following instructions, disregard heating

or air conditioning directions if not applicable to

your system.

CAUTION

Compressor Damage Hazard.

Operating at too low of an outdoor

temperature can cause compressor damage.

Do not operate cooling if outdoor temperature is

below 50°F (10°C).

Allow compressor to remain off for five minutes

before restarting.

Refer to manufacturer’s recommendations.

❑Turn on power to the heating/air conditioning system.

❑Observe system operation for at least one cycle on

both heating and air conditioning. To observe:

❑Place the System switch at the Heat position and the

Fan switch at the Auto position. Move the temperature

setting lever 10°F (6°C) below room temperature. The

heating equipment should turn on. A short warmup

period may be required before system fan turns on.

NOTE: Some systems have a time delay that can pre-

vent operation up to five minutes.

❑Turn the Fan switch to On. The system fan should turn

on and operate continuously. The system blower

should continue to operate at any System switch or

thermostat setting.

5 THERMOSTAT

❑Place the System and Fan switches at the desired

settings for operation.

6 TROUBLESHOOTING (TABLE 2)

Your Honeywell thermostat requires little or no attention.

Most problems can be resolved according to Table 2.

NOTE: If your system is heating-only or air

conditioning-only, disregard sections not

applicable to your system.

CT41A HEATING/COOLING THERMOSTAT

569-0788-2

Table 2. Recommended Corrective Action for Your System.

Symptom Problem Corrective Action

No heat System switch is at Off of Cool position. Move System switch to Heat position.

Blown fuse or tripped circuit breaker. Replace fuse or reset circuit breaker.

Furnace power switch is at Off. Turn furnace power switch to On.

No pilot flame. Relight pilot flame according to furnace

manufacturer instructions.

Incorrect connections to thermostat. With power to furnace at Off, tighten all

mounting and terminal screws. Repair frayed or

broken wires.

Other. Contact a qualified service technician for

assistance.

Furnace turns on and

off.

Burner On period is too short. Remove the thermostat cover and move the

heat anticipator lever counterclockwise (left)

one scale mark. Replace the cover and wait

several hours for the system to stabilize.

Major swings in

temperature greater

than 2°F (1°C) when

outside temperature is

stable.

Burner On period is too long. Remove the thermostat cover and move the

heat anticipator lever clockwise (right) one

scale mark. Replace the cover and wait several

hours for the system to stabilize.

Thermostat setting and

thermometer reading

disagree.

Thermostat is not level. Recheck the thermostat position on the wall.

Use bubble level to make sure it is level. See

step 3 and Fig. 5.

Thermostat is affected by drafts or radiant

heat.

Contact a qualified service technician to change

the location.

Thermometer is out-of-calibration. Recalibrate. See step 7.

No air conditioning. System switch is in Off or Heat position. Move switch to Cool position.

Blown fuse or tripped circuit breaker. Replace fuse or reset circuit breaker.

Compressor switch (located outdoors) is

turned off.

Move switch to On position.

Incorrect connections to thermostat. With power to system off, tighten all mounting

and terminal screws. Repair broken wires.

Other. Contact service technician for assistance.

CT41A HEATING/COOLING THERMOSTAT

69-0788-2 6

7 RECALIBRATE THERMOMETER

If the thermostat setpoint and the thermometer reading

do not agree, the thermometer may need recalibration.

Follow this procedure:

❑Remove thermostat cover.

❑Set the cover on a table near an accurate

thermometer.

❑After allowing five or ten minutes for stabilization,

compare the readings.

❑If the readings are the same, replace the cover and

put the system into operation.

❑If the readings are different, insert a hex head wrench

into the thermostat shaft and turn it until the

thermometers have the same reading. See Fig. 8.

❑Replace cover and put the system into operation.

Fig. 8. Adjusting thermometer calibration.

8068

BACKSIDE

OF COVER

THERMOMETE

SHAFT

HEX HEAD

WRENCH

CT41A HEATING/COOLING THERMOSTAT

769-0788-2

Limited One-Year Warranty

Honeywell warrants this product, excluding battery, to be free from defects in the workmanship or materials, under normal use and service, for a period of

one (1) year from the date of purchase by the consumer. If, at any time during the warranty period, the product is defective or malfunctions, Honeywell shall

repair or replace it (at Honeywell’s option) within a reasonable period of time.

If the product is defective,

(i) return it, with a bill of sale or other dated proof of purchase, to the retailer from which you purchased it, or

(ii) package it carefully, along with proof of purchase (including date of purchase) and a short description of the malfunction, and mail it, postage prepaid,

to the following address:

Honeywell Return Goods Canada: Honeywell Limited/Honeywell Limitée

Dock 4, MN10-3860 Product Services ON15

1885 Douglas Dr N 35 Dynamic Dr

Golden Valley, MN 55422 Scarborough, Ontario M1V 4Z9

This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the defect or malfunction was

caused by damage which occurred while the product was in the possession of a consumer.

Honeywell’s sole responsibility shall be to repair or replace the product within the terms stated above. HONEYWELL SHALL NOT BE LIABLE FOR ANY

LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING, DIRECTLY OR INDIRECTLY,

FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR IMPLIED, OR ANY OTHER FAILURE OF THIS PRODUCT. Some states do not allow the

exclusion or limitation of incidental or consequential damages, so this limitation may not apply to you.

THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. THE DURATION OF ANY IMPLIED

WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO

THE ONE YEAR DURATION OF THIS WARRANTY. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation

may not apply to you.

This warranty gives you specific legal rights, and you may have other rights which vary from state to state.

If you have any questions concerning this warranty, please write Honeywell Customer Relations, 1985 Douglas Dr N, MN10-1461, Golden Valley, MN

55422. In Canada, write Retail Products ON15, Honeywell Limited/Honeywell Limitée, 35 Dynamic Dr, Scarborough, Ontario M1V 4Z9.

69-0788—2 G.H. Rev. 10-03 www.honeywell.com/yourhome

CT41A HEATING/COOLING THERMOSTAT

Printed in U.S.A. on recycled

paper containing at least 10%

post-consumer paper fibers.

Automation and Control Solutions

Honeywell International Inc. Honeywell Limited-Honeywell Limitée

1985 Douglas Drive North 35 Dynamic Drive

Golden Valley, MN 55422 Scarborough, Ontario

M1V 4Z9

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