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Copyright © 2003 Honeywell International Inc •   

 • All Rights 

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

MERCURY
SWITCH

TYPICAL LOCATION OF A MERCURY 
SWITCH 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

Summary of Contents for CT41A

Page 1: ...te 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 mar...

Page 2: ... 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 fr...

Page 3: ...e 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 antic...

Page 4: ... 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...

Page 5: ... 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 t...

Page 6: ...ate 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 calib...

Page 7: ...on 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 A...

Page 8: ...OSTAT 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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