Honeywell RTH9585WF - User Manual

Honeywell RTH9585WF

A user manual for Honeywell Home thermostats covers essential wiring configurations when a common (C) power wire is missing during installation or replacement. The document addresses two primary scenarios: locating an unused C-wire in the wall or using the G-wire as a temporary solution for compatible heating/cooling systems, with clear guidance on system compatibility. It also includes safety warnings to ensure proper electrical disconnection before working and diagrams illustrating terminal connections.

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Table of Contents:

Page 1 – Handling Missing C Wire During Installation
Page 2 – Wiring Modification Steps
Page 3 – Installing Thermostat with C-wire Requirements
Page 4 – Rewiring HVAC Unit Connections
Page 5 – Installing Thermostat with Alternative Cabling
Page 6 – Modifying HVAC Control Panel Wiring

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C Wire Addendum

Customer Support
1-855-733-5465

Important!

This thermostat requires a C, or common, wire for power.

If you are replacing an existing thermostat, it might not have a C wire connected to it.

If you don’t see a C wire, try one of these two options to power your new thermostat. Please
contact Customer Support at 1-855-733-5465 for assistance at any time during this process.

Before beginning these steps, turn OFF power to your heating/cooling system.

Option A: Finding the C wire

1 There might be an extra wire pushed into the wall or wrapped

around the wire bundle. Gently pull the wire bundle out of the
wall to check for unused wires.

2 If you have an unused wire, connect that wire to the C terminal

on your new thermostat.

3 Connect the other end of the C wire to the C terminal on your

heating/cooling system (or the zone panel if your home uses
more than one thermostat to control heat and cool). Be sure
the other wire(s) connected to the C terminal stay securely
connected when you re-tighten the C terminal.

Note:

Not all heating/cooling equipment use the C label for the 24 VAC common wire. If your

heating/cooling equipment does not have a C terminal, check the system manual or contact
the manufacturer to find out which terminal is the 24 VAC common.

4 Complete the installation following the steps in the instruction manual or quick start guide.

Option B: Using the G wire

If there is no unused wire in the wall, check the table below to see if you can use the G wire to
power the thermostat. If you can’t use the G wire, contact Customer Support.

Note:

Using the G wire in this manner means you can’t run your system fan continuously. It will

run when the system is heating or cooling.

Heating/Cooling System

Furnace that burns gas or propane

Use G wire

Furnace that burns oil

Call Customer Support at 1-855-733-5465

Heat pump WITHOUT backup (auxiliary) heat

Use G wire

Heat pump WITH backup (auxiliary) heat

Call Customer Support at 1-855-733-5465

Zoned system (more than one thermostat

controlling the heating/cooling system)

Call Zoning Support at 1-800-828-8367

System with a whole-house humidifier,

dehumidifier, or ventilator

Call Customer Support at 1-855-733-5465

M36727

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About this manual

Brand: Honeywell
Model: RTH9585WF
Document type: User Manual
Category: Thermostat
Language(s): English
Pages: 8
File size: 1 MB
Format: PDF

Other Manuals for Honeywell RTH9585WF

Summary

Page 1 - Handling Missing C Wire During Installation

Options for wiring without a C wire, including using an unused wire or the G wire, and safety precautions before starting work.

Page 2 - Wiring Modification Steps

Step-by-step instructions for modifying thermostat wiring by relocating the G wire to the C terminal and connecting the Y terminal to the G terminal using a jumper wire, illustrated with diagrams.

Page 3 - Installing Thermostat with C-wire Requirements

Guidance for installing a thermostat requiring a C-wire, detailing options to locate an unused C-wire or use a G-wire, along with system compatibility information and wiring diagrams.

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