Honeywell RTH221B1039/U1 User Manual

Owner’s Manual
Read and save these
instructions.
For help please visit
honeywellhome.com
RTH2300/RTH221
Series
Programmable
Thermostat
M37777
Heat Off Cool Auto On
Fan
Heat Off Cool
Auto On
Fan
Set
Hold
Run
Identify System Type
This thermostat is compatible with the following systems:
• Gas, oil or electric furnace
• Central air conditioner
• Hot water system with or without pump
• Millivolt system
• Central heating and cooling system
• Heat pump without auxiliary/backup heat
Do you need assistance? We are here to help.
Visit http://honeywellhome.com/support for wiring assistance before returning the
thermostat to the store.
This thermostat cannot be used on heat pumps with backup heat or on
multistage systems.

Honeywell RTH221B1039/U1 Specifications

General

Brand	Honeywell
Model	RTH221B1039/U1
Category	Thermostat
Language	English

Summary

Customer Assistance

Installation Process

Turn Off Power

Ensure power to the heating/cooling system is turned off before proceeding with installation.

Remove Old Thermostat

Instructions for safely removing the existing thermostat from the wallplate.

Label Wires with Tags

Guidance on labeling wires using provided tags for correct connection.

Separate Wallplate

Mount Wallplate

Instructions for mounting the new wallplate securely to the wall.

Connect Wires

Guide to connecting wires to the thermostat terminals based on labels.

Install Thermostat onto Wallplate

Steps to attach the thermostat unit to the mounted wallplate.

Turn Power Back On

Instructions to restore power to the heating/cooling system after installation.

Programming and Operation

Adjusting Program Schedules

Built-in Compressor Protection

Advanced Installation and System Setup

Thermostat Controls Overview