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3 69-1638—1
Step 1. Prepare for Installation1. Carefully unpack your new thermostat. Save your receipt and make sure you have the following parts:
• Thermostat and mounting plate
• Labels
• Screws and anchors
• Installation and Programming Instructions
2. Gather the needed tools and supplies listed below.
3. Make sure that your heating and cooling systems are working properly. If there is a problem with either system,
call a heating/air conditioning contractor—the problem may persist after you install the new thermostat.
IMPORTANT:
To avoid damaging the compressor in the air conditioner, do not operate the cooling system when the tem-
perature outdoors is below 50°F (10°C).
Steam
A steam boiler with radiator heat.
No CT3600
Heat Pump
Heating and cooling are produced from the same outdoor unit (compressor) with
no auxiliary or backup heat.
No CT3600
Multistage Heat Pump
Heating and cooling are produced from the same outdoor unit (compressor) with
auxiliary or backup heat.
No CT3611
Multistage Conventional
A heating or cooling system with more than one stage.
No See your
contractor
Required Tools and Supplies Optional Tools
• Two AA alkaline batteries. Honeywell recommends Energizer®
batteries.
• Screwdriver.
• Hand or power drill with 3/16-inch or 7/32-inch drill bit.
• Pencil.
• Wire cutter/stripper or sharp knife.
• Level.
• Electrical tape.
Heating/Cooling System
Compatible
with CT2800? Alternate Model