Honeywell RTH7400 Programmable Thermostat Owners Guide

Honeywell RTH7400 Owners Guide

The RTH7400D Thermostat provides electronic control of 24 Vac heating and cooling systems or 750 mV heating systems.

Honeywell RTH7400 Table of Content

Prepare for Installation ........................................................... 3
Follow Important Instructions .................................................. 5
Remove Old Thermostat ......................................................... 6
Follow Special Instructions...................................................... 7
Label Old Thermostat Wires .................................................. 10
Mount New Wallplate to Wall ................................................. 11
Connect Wires to New Wallplate............................................. 15
Install Batteries..................................................................... 23
Attach New Thermostat to Wallplate ...................................... 24
Configure Installer Setup........................................................ 26
Customer Assistance ........................................................... 62
Limited One-Year Warranty.................................................... 63

Honeywell RTH7400 Prepare for Installation

Step 1. Prepare for Installation

Check that you have everything required for the installation:

  • • Two AA alkaline batteries
  • • No. 2 Phillips screwdriver and standard pocket screwdriver
  • • Drill
  • • Drill bit—use 3/16 in. for drywall; use 7/32 in. for plaster
  • • Level (optional)
  • • Hammer
  • • Pencil
  • • Electrical tape

Step 2. Follow Important Instructions

  1. Do not connect the wires to the new thermostat based on wire color because damage can occur to the heating and/or cooling system. These Installation Instructions explain later how to use the enclosed wire labels to correctly mark the wires connected to your old thermostat.

Step 3. Remove Old Thermostat

  1. Turn off power at the heating and/or cooling system or fuse/circuit breaker panel.
  2. Remove the cover from the old thermostat.
  3. Remove the old thermostat from the wall or wallplate. Do not remove the wires.

Honeywell RTH7400 Prepare for Installation

Step 4. Follow Special Instructions

  1. If you have two C and/or C1 wires connected to your old thermostat, do not connect them to your new thermostat.
  2. Disconnect the C and/or C1 wires. Make sure they do not touch each other or any other wires.
  3. Wrap the bare end of each C and/or C1 wire with electrical tape.

Readmore and Download Honeywell RTH7400 Owners Guide PDF Below

Honeywell RTH7400 Owners Guide