Honeywell CT3451 User Manual

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 •All Rights Reserved 

69-1620-1

Programmable Heat and/or Cool

Low Voltage (20 to 30 Vac) Thermostat and Wallplate

Congratulations on the purchase of your new thermostat! 
More than 100 years of Honeywell engineering produced 
this thermostat that can provide you with a more 
comfortable and convenient living environment.

Your new thermostat automatically controls the 
temperature in your home, keeping you comfortable 
while saving energy when programmed according to 
these instructions.

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.

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. 

❑

Check Table 1 to make sure this thermostat is 
compatible with your system. If not, return it to the 
retailer.

❑

Acquire tools and items, as needed. See Fig. 1.

M10614

MERCURY
SWITCH

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