Honeywell CT3500 Programmable Thermostat User Guide

June 17, 2024
Honeywell

Honeywell CT3500 Programmable Thermostat

Total comfort temperature management with Smart Response™ Technology.
Congratulations! You made a smart choice by purchasing your new Honeywell thermostat the smart thermostat that;

  • Keeps you comfortable by automatically calculating exactly when the furnace or air conditioning should go on to have the house at the desired comfort temperature by the time you wake up or return home.
  • Saves the maximum amount of energy and money by automatically remembering to adjust the temperature when you leave home or go to sleep.
  • Provides the ultimate in comfort and convenience. It comes preprogrammed. You can use the preprogrammed schedule, or set your own.
  • This manual answers many of the questions that can arise as you become familiar and comfortable with your Honeywell thermostat — the state-of-the-art in-home comfort controls.
  • Read these instructions carefully. Failure to follow these instructions can damage the product or cause a hazardous condition.

MERCURY NOTICE

  • If this thermostat is replacing a control that contains mercury in a sealed tube, do not place your old control in the trash. Contact your local waste management authority for instructions regarding recycling and the proper disposal of this control, or of an old control containing mercury in a sealed tube.
  • If you have questions, call Honeywell Inc. at 1-800-468-1502.

PREPARE FOR INSTALLATION

Check Table 1, the compatibility chart, to make sure the thermostat is compatible with your system. If your system is not compatible, call Honeywell Customer Relations Center, toll-free, 1-800-468-1502.

Table 1. Compatibility Chart

System Type Compatibility with CT3500/CT3595
Gas — Standing Pilot Yes
Gas — Electronic Ignition Yes
Gas-fired Boilers Yes a
Gas — 750 Millivolt Heat only b Yes
Oil-Fired Boilers Yes a
Oil-Fired Furnace Yes
Electric Furnace Yes
Electric Air Conditioning Yes
Baseboard Electric (120/240 line volt)c No
Single-Stage Heat Pump Yes
Multistage Heat Pumps/Multistage Equipment No
  • Compatible with 2-wire Honeywell and Taco zone valves. Not compatible with 3-wire zone valves or 2-wire White Rodgers no. 1361 zone valves.
  • The Millivolt system must be heating only.
  • Not compatible with any 120/240-volt system.

Package Contents

  • Thermostat
  • Wiring labels
  • Wallplate
  • 3 Energizer® AA batteries
  • Screws and anchors
  • Owners manual

Tools Required

  • Screwdriver
  • Drill

REMOVE OLD THERMOSTAT

  • Test your heating and cooling systems to make sure they work properly. If either system does not work, contact your local heating/air-conditioning dealer. To avoid compressor damage, do not operate the cooling system when the outdoor temperature is below 50°F (10°C).
  • Turn off power to the system at the furnace or the fuse/circuit breaker panel.
  • Carefully unpack your new thermostat and wallplate. Save the package of screws, instructions, and receipt.
  • Remove the cover from the old thermostat. If the cover does not snap off when pulled firmly from the bottom, check for a screw or screws used to lock on the cover.
  • Loosen the screw or screws holding the thermostat to the wallplate and lift the thermostat away.
  • Disconnect the wires from the old thermostat. As you disconnect each wire, attach the enclosed labels with the old terminal designation. If there are only two wires, they do not need to be labelled. Wrap the wires around a pencil as shown to keep them from falling back into the wall.

Special Installations
Read this section if you are replacing:

  • Clock thermostat with separate wires for the clock.
  • Thermostat with six or more wires connected to it.
  • The thermostat in a heating-only system with three wires.

Replacing a Clock Thermostat that has C or C1 Clock Terminals
If you are replacing a Honeywell Chronotherm® Thermostat, you may find one or two wires going to the C or C1 clock terminals on the Chronotherm wiring wallplate. Do not allow them to touch, or you can damage the transformer. Disconnect the wires and wrap them separately using electrical tape. Do not wrap them together. Place the wires where they will not interfere with the operation of the new thermostat. Record the colours and terminal designation labels of the remaining wires.

Replacing a Thermostat that has Six or More Wires
If there are six or more wires (excluding clock wires attached to terminals), you probably have a variation of a multistage heat pump or other multistage system. This thermostat is not compatible with multistage systems, so return the product to the place of purchase. For information about which programmable thermostats will work with your system, call Honeywell Customer Relations Center, at 1-800-468-1502.

Replacing a Thermostat that has Three Wires
If you have three wires for a heating-only system and can operate the fan using the fan ON switch this thermostat works with your system. However, some hot water (zoned) heating systems also have three wires. Your thermostat will work only if you install an isolating relay on these systems. For details, call your local heating and/or cooling contractor.

MOUNT THERMOSTAT WALLPLATE

  • Separate the wallplate from the thermostat by placing your thumb or fingers between the bottom of the wallplate and the thermostat, and pulling the wallplate up and away from the thermostat. See the illustration at right.

  • Position the wallplate on the wall. Level the wallplate for appearance if desired. Use a pencil to mark the two mounting holes that best fit the application.

  • Remove the wallplate from the wall. Drill two 3/16 in. holes in the wall (if drywall) as shown. For materials such as plaster or wood, drill 7/32 in. holes where marked. Gently, tap the (provided) anchors into the drilled holes until they are flush with the wall.

  • Reposition the wallplate over the holes. Pull the wires through the wiring opening. Loosely insert mounting screws into each of the holes

  • Level the wallplate if desired. The thermostat functions properly when not level.

  • Tighten mounting screws.

WIRE WALLPLATE TERMINALS

IMPORTANT
All wiring must comply with local codes and ordinances. If unsure about household wiring procedures, call your local heating/air-conditioning contractor.

  • Refer to the labels you placed on the wires when you removed the old thermostat (see illustration).

  • Match the letter of your old thermostat wire with the corresponding terminal letter on your new thermostat. Refer to Table 2.

  • Remove the factory-installed jumper connecting terminals R and RC if wires are connected to both of those terminals.

  • For wiring diagrams, if needed, see pp 21-22.

  • Loosen the terminal screws. Slip each wire beneath its matching terminal. Wraparound and straight connections are both acceptable, (see illustration). Tighten the terminals.

  • Plug the hole in the wall with insulation to help prevent drafts from adversely affecting thermostat operation.

Table 2. Terminal Designations on Old and New Thermostats

Terminal on Old Thermostat Connect To Description
R, RHa, 4, V R Power
Rc, Ra Rc Power for cooling
W, W1, H W Heat
Y, Y1, M Y Cooling
G, F G Fan
O O Changeover is cool. (Single-stage heat pump only).
Bb Bb The changeover in heat. (Single-stage heat pump only).
Cc, Xc, Bb Do not connect. Transformer common
W2, H2 Do not continue the installation. Call
1-800-468-1502. Second stage heat.
Y2 The second stage is cool.
  • If both RH and R terminals are present on the existing thermostat, remove the jumper and connect Rh to R and R to Rc.
  • Do not connect both O and B when wiring to a single-stage heat pump. Connect O to O. Tape off B.
  • Tape off the end of the wire with electrical tape and push the taped wire back into the wiring hole in the wall.

INSTALL THE BATTERIES

IMPORTANT
Three AA alkaline batteries are included with the thermostat.
Batteries must be installed for the programming and operation of the thermostat and the heating/cooling system.

  • Install the batteries in the wallplate so the positive terminals all point up (see illustration).
  • If the thermostat is already mounted on the wall, remove the thermostat by placing your thumb between the thermostat and wallplate and pulling the thermostat up and away as shown.
  • When the batteries are running low, a REPL BAT message flashes for one to two months before the batteries run out completely. Replace the batteries as soon as possible once the message flashes.

IMPORTANT
Although the thermostat has a low battery indicator, replace the batteries once per year to prevent leakage and to prevent the thermostat and heating/cooling system from shutting down due to lack of battery power in the thermostat.

  • If you insert new batteries within 20 to 30 seconds of removing the old batteries, the system retains the current time and day. If the display is blank, the batteries are dead or installed incorrectly. You must reset the time and day. Refer to Set the Clock for instructions.
  • As a precaution when leaving home for longer than a month, change batteries before leaving to prevent the system from shutting down due to lack of power. Always use fresh alkaline batteries. Nonalkaline batteries do not last as long. They also can leak, causing damage to the thermostat and the wall surface. Honeywell recommends Energizer® batteries.

SET FAN OPERATION SWITCH
The thermostat fan operation switch, labeled FUEL SWITCH is factory set in the F position. This is the correct setting for most systems. If your system is an electric heat system, set the switch to E. The E setting allows the fan to turn on immediately with the heating or cooling in a system where the G terminal is connected.

MOUNT THE THERMOSTAT

CUSTOMIZE YOUR THERMOSTAT

Your Honeywell thermostat comes preset to the most commonly used settings. The settings are:

  • Gas or oil-forced air furnace.
  • Smart Response technology on.
  • Temperature °F.
  • 12-hour clock format.

You can change any or all of these settings.
IMPORTANT
Always press the keys with your fingertip or a similar blunt tool. Sharp instruments like pens and pencil points can damage the keyboard.

  • Press and hold down, , and, simultaneously until the screen shows.
  • You now can change any of these settings.

System Type (Feature Number 4)
System-type options are

  • 1 = Gravity or steam system.
  • 3 = Hot water, high-efficiency furnace (90% or better), or single-stage heat pump.
  • 6 = Gas or oil-forced air furnace (preset).
  • 9 = Electric furnace.

To change your system type

  • Press until the display shows your furnace or boiler type.
  • Press Time to move to the next feature or to return to the main display.

Smart Response™ Technology (Feature Number 13)

  • Smart Response technology options are:
  • 0 = Smart Response technology on (preset).
  • 1 = Smart Response technology off.
  • To turn Smart Response technology on or off:
  • Press once.
  • Press Time to move to the next feature or to return to the main display.

NOTE: See Smart Response technology (page 20) for information about this feature.

Temperature Format (Feature Number 14)

  • Temperature format options are:
  • 0 = °F (preset).
  • 1 = °C.
  • To change temperature format:
  • Press once.
  • Press Time to move to the next feature or to return to the main display.

Time Format (Feature Number 16)

  • Time format options are:
  • 0 = 12-hour clock (preset).
  • 1 = 24-hour clock.
  • To change the time format:
  • Press once.
  • Press to return to the main display.

Factory Set Function (Feature Number 37)
Do not change this setting.

SET THE CLOCK
Set Current Day and Time
NOTE: On initial power-up, the screen flashes 1:00 pm until you press a key.

  • Press .
  • Press until the screen shows the current day.
  • Press time until the screen shows the current time. (Tapping the will advance the time in one-hour increments).
  • Press .

PROGRAMMING
The keyboard is located behind the thermostat cover. The three most frequently used keys are near the display.

Pressing displays the current temperature settings. Pressing the keys changes the temperature. The thermostat displays the day, time, program period, temperature and system settings.

There is an individual key for each of the four program periods:

  • The program period is when you want the house at a comfortable temperature when you get up and while you get ready for work or school. (This is a higher temperature during the heating season and a lower temperature during the cooling season).
  • The program period you can set for an energy-saving temperature while you are away at work or school. (This is a lower temperature during the heating season and a higher temperature during the cooling season).
  • The program period is when you want the house at a comfortable temperature for activities before bedtime. (This is a higher temperature during the heating season and a lower temperature during the cooling season).
  • The program period you can set for an energy-saving temperature while you sleeping. (This is a lower temperature during the heating season and a higher temperature during the cooling season).

Table 3 can be helpful when planning your schedule of time and temperature settings. The thermostat preprogrammed settings are shown in parentheses ( ).

Table 3. Personal Programming Table.

Period| Default Setting| Weekday (Mon-Fri)| Saturday (Sat)| Sunday (Sun)
---|---|---|---|---
Wake| Time (6:00 AM)| | |
Heata (70°F/21°C)| | |
Coolb (78°F/25.5°C)| | |
Leave| Time (8:00 AM)| | |
Heata (62°F/16.5°C)| | |
Coolb (85°F/29.5°C)| | |
Return| Time (6:00 PM)| | |
Heata (70°F/21°C)| | |
Coolb (78°F/25.5°C)| | |
Sleep| Time (10:00 PM)| | |
Heata (62°F/16.5°C)| | |
Coolb (82°F/28°C)| | |

  • Your heating setpoints cannot be higher than 90°F (32°C) or lower than 40°F (4.5°C).
  • Your cooling setpoints cannot be higher than 99°F (37°C) or lower than 45°F (7°C).

Program Weekdays
Start by programming the wake time and temperature for weekdays.

  • Press and release .

  • Press until (Mon-Fri) displays.

  • Press Time or key until the desired time shows in the display.
    NOTE: Program times are in 15-minute intervals. For example, 8:00, 8:15, 8:30.

  • Press or key until the desired wake temperature displays.

The setpoint temperature range is 40°F to 90°F (4.5°C to 32°C) for heating and 45°F to 99°F (7°C to 37°C) for cooling.

  • Press to switch between heating and cooling setpoints.
    NOTE: Program times are the same for heating and cooling.

  • Press or until the display shows the desired temperature setpoint.

  • Press, or repeat these steps each time. Your weekday is now programmed.

Program Saturday and Sunday
Repeat each step in Program Weekdays for Saturday and Sunday.

  • Press when the entire week is programmed.

Clear a Program Period
NOTE: Wake cannot be cleared.

  • Press, or for the program period you want to clear.
  • Press until the desired day displays (Mon-Fri Sat; Sun).
  • Press and hold the, or for approximately 3 seconds until the time and temperature clear.
  • Repeat the above steps for each period to be cleared.
  • Press .

OPERATING YOUR THERMOSTAT
Change Temperature Setting Until the Next Program Period (Temporary Change)

  • Press until the screen shows the desired temperature setting.
    NOTE: The temporary temperature setting is displayed for about 3 seconds and then the room temperature is displayed.

  • Temporary appears in the display. The setting cancels when the next program period starts or when you press .

Change Temperature Setting Indefinitely (Hold)

  • Move the System switch to the desired position (Heat or Cool).
  • Press the or to change your setting if desired. (The display changes from showing the setpoint temperature to room temperature after approximately three seconds).
  • To cancel “Hold” press .

Change the Temperature Setting Until a Designated Day and Period (Vacation Hold)

  • Press twice.
  • Press or until the display shows the desired temperature setpoint.
  • Press Time until the desired number of days that you will be away (1 through 255) is displayed.
  • Press, or select the program period when you want the program to restart.

NOTE: If the Vacation Hold needs to be cancelled before the designated time, press to return to the program.

SET THE FAN AND SYSTEM SWITCHES

First, set the fan switch

  • Fan On: The fan runs continuously. Use for improved air circulation or more efficient central air cleaning. (In a heat-only system, the fan runs continuously only if the fan relay is connected to the G thermostat terminal).
  • Fan Auto: Normal setting for most homes. The equipment controls the fan operation.

Then set the system switch.

  • Heat: The thermostat controls your heating system.
  • Off: Both the heating and air conditioning systems are off.
  • Cool: The thermostat controls your air conditioning system.

IF YOU HAVE A PROBLEM

Table 4. Solution Guide

If… Then…
The display does not appear. •      Make sure the batteries are installed

correctly.

•      Make sure the thermostat is mounted and latched on the wallplate. Mount and latch the thermostat on the wallplate if it is not.

Temperature settings will not change (for example; cannot set the heating higher or the cooling lower).| •      Make sure the temperature setpoints are:

—40 to 90°F (4.5 to 32°C) for heating.

—45 to 99°F (7 to 37°C) for cooling.

The heating does not come on.| •      Make sure the heating setpoint is above the room temperature.

•      Make sure the circuit breaker is not tripped, and reset it if necessary.

•      Make sure the power switch at the equipment is in the On position and set it to On if it is in the Off position.

•      Wait five minutes for the system to respond.

•      Set the system switch to Heat.

If… Then…
Cooling does not come on. •      Make sure the cooling setpoint is below the

room temperature.

•      Make sure the circuit breaker is not tripped, and reset it if necessary.

•      Make sure the system switch at the air conditioner is in the On position, and set it to On if it is in the Off position.

•      Wait five minutes for the system to respond.

•      Set the system switch to Cool.

The system on indicator ( = heat, = cool) is lit, but no warm or cool air is coming from the registers.| Wait five minutes after seeing the flame or snowflake and check the registers again. If there is no hot or cool air coming from the registers, refer to Heating does not come on or Cooling does not come on. If all of this has been checked, contact your local heating and cooling contractor.
Display flashes during programming.| The temperature setting limit has been reached. The heating setting range is 40 to 90°F (4.5 to 32°C). The cooling setting range is 45 to 99°F (7 to 37°C).
Temperature changes occur at the wrong times.| •      Check the program times for the period in question.

•      Make sure the AM and PM settings are correct.

•      Make sure the current time and day settings are correct.

•      Reprogram any incorrect settings.

NOTE:     If your thermostat is set for Smart Response™ technology, the start times occur before your programmed comfort period.

Toll-Free Customer Assistance
Please read and follow the provided instructions for this thermostat. For additional information, go to www.honeywell.com/yourhome or call the Honeywell Customer Relations Center at 1-800-468-1502. The Center hours are Monday through Friday, 7:00 AM to 5:30 PM Central Time.

Before calling, please have the following information available

  • Thermostat model number. (Located on the back of the thermostat).
  • Thermostat date code. (Located below model number).
  • Type of heating/cooling system (for example, hot water, warm air, oil, or gas).
  • Location and number of wires connected to the thermostat.

SMART RESPONSE™ TECHNOLOGY

Your thermostat is a small computer. The Smart Response technology calculates the correct time of day to turn on your heating or cooling system. Smart Response technology considers the following information.

  • Air temperature.
  • Wall temperature.
  • The time of day when you want the comfort temperature established.

When the thermostat activates Smart Response technology, the thermostat displays In Recovery, changes the setpoint, and turns on the system.

  • Your thermostat learns from experience. Each day it checks how closely it hit the recovery target and then adjusts the next day’s recovery start time accordingly.
  • It takes a few days after installation for the thermostat to adjust to the local weather, your lifestyle, the construction of your home, and your heating/cooling system.
  • You can turn off Smart Response technology by selecting Conventional Recovery. See Step 8. Customize Your Thermostat.

THE THERMOSTAT USES THE SAME SCHEME TO RETURN TO LOWER COMFORT TEMPERATURE DURING THE COOLING SEASON.

IF In Recovery IS DISPLAYED, PRESS TO SEE THE COMFORT SETPOINT.

When the thermostat activates Smart Response technology, the thermostat displays In Recovery, changes the setpoint, and turns on the system.

  • Your thermostat learns from experience. Each day it checks how closely it hit the recovery target and then adjusts the next day’s recovery start time accordingly.
  • It takes a few days after installation for the thermostat to adjust to the local weather, your lifestyle, the construction of your home, and your heating/cooling system.
  • You can turn off Smart Response technology by selecting Conventional Recovery. See Step 8. Customize Your Thermostat.

WIRING DIAGRAMS

Limited One-Year Warranty

Honeywell warrants this product, excluding battery, to be free from defects in the workmanship or materials, under normal use and service, for one (1) year from the date of purchase by the consumer. If, at any time during the warranty period, the product is defective or malfunctions, Honeywell shall repair or replace it (at the Honeywell option) within a reasonable period.

If the product is defective

  1. return it, with a bill of sale or other dated proof of purchase, to the retailer from which you purchased it, or
  2. package it carefully, along with proof of purchase (including date of purchase) and a short description of the malfunction, and mail it, postage prepaid, to the following address:
  • Honeywell Inc. USA Honeywell Canada:
  • Dock 4 — MN10-3860 Honeywell Limited/Honeywell Limitée
  • 1885 Douglas Drive North 35 Dynamic Drive
  • Golden Valley, MN 55422-3992 Scarborough, Ontario M1V 4Z9

This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the defect or malfunction was caused by damage that occurred while the product was in the possession of a consumer.
Honeywell’s sole responsibility shall be to repair or replace the product within the terms stated above. HONEYWELL SHALL NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING, DIRECTLY OR INDIRECTLY FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR IMPLIED, OR ANY OTHER FAILURE OF THIS PRODUCT. Some states do not allow the exclusion or limitation of incidental or consequential damages, so this limitation may not apply to you.
THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. THE DURATION OF ANY IMPLIED WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO THE ONE-YEAR DURATION OF THIS WARRANTY. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.
This warranty gives you specific legal rights, and you may have other rights which vary from state to state.
If you have any questions concerning this warranty, please write our Customer Relations Center, Honeywell Inc., 1885 Douglas Dr N., Golden Valley, MN 55422-3992, or call 1-800-468-1502, Monday-Friday, 7:00 a.m. to 5:30 p.m., Central time. In Canada, write Retail Products ON30 Honeywell Limited/Honeywell Limitée, 155 Gordon Baker Road, North York, Ontario M2H 3N7.

CONTACT

Home and Building Control

  • Honeywell
  • 1985 Douglas Drive North
  • Golden Valley, MN 55422

Home and Building Control

Printed in the U.S.A. on recycled paper containing at least 10% post-consumer paper fibres.

References

Read User Manual Online (PDF format)

Read User Manual Online (PDF format)  >>

Download This Manual (PDF format)

Download this manual  >>

Honeywell User Manuals

Related Manuals