Honeywell RTHL3550 Non-Programmable Digital Thermostat Installation Guide

RTHL3550 Non-Programmable
Digital Thermostat
Owner’s Manual

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For help please visit yourhome.honeywell.com

Installation is Easy

1. Label wires and remove your old thermostat
2. Install and wire your new thermostat
3. Set your new thermostat to match your heating/cooling system
   • It is preset for the most common system

Do you need assistance? We are here to help.
Call 1-800-468-1502 for wiring assistance before returning the thermostat to the store.
This thermostat works on 24 volt or 750 mV systems. It will NOT work on 120/240 Volt systems.

ATTENTION: MERCURY RECYCLING NOTICE
This product does not contain mercury. However, this product may replace a product that contains mercury. Mercury and products containing mercury should not be discarded in household trash.
For more information on how and where to properly recycle a thermostat containing mercury in the United States, please refer to the Thermostat Recycling Corporation at
www.thermostat-recycle.org.
For mercury thermostat recycling in Canada, please refer to Switch the Stat at www.switchthestat.ca

NOTICE: To avoid possible compressor damage, do not run air conditioner if the outside temperature drops below 50°F (10°C).
Customer assistance
For assistance with this product, please visit
http://yourhome.honeywell.com.
Or call Honeywell Customer Care toll-free at
1-800-468-1502.
To save time, please note your model number and date code before calling.
Remove the battery holder; the model number is on the battery holder.

® U.S. Registered Trademark. Patents pending.
US Patent No. D542,677; 7,832,652; 7,641,126 and other patents pending.

Installation

Turn Off Power to Heating/Cooling System

Remove Old Thermostat

Remove old thermostat but leave wallplate with wires attached.

If you have an older thermostat with a sealed mercury tube, turn to page 2 for proper disposal instructions.

Label Wires with Tags
Label the wires using the supplied wire labels as you disconnect them.

Separate Wallplate from New Thermostat
Remove the wallplate from the new thermostat and mount it onto the wall.

Mount Wallplate
Mount the new wallplate using the included screws and anchors.

Drill 3/16-in. holes for drywall
Drill 3/32-in. holes for plaster

Connect Wires
Simply match wire labels.
If labels do not match letters on the thermostat, check “Alternate Wiring (Conventional Systems)” on page 6 and connect to the terminal as shown (see notes, below).

We are here to help. Call 1-800-468-1502 for wiring assistance.

Alternate Wiring (Conventional Systems)
If labels do not match terminals, connect wires as shown here (see notes, below).

1. If wires will be connected to both R and Rc terminals, remove the metal jumper.
2. Do not use C, X, or B. Wrap the bare end of the wire with electrical tape.

Wiring—Heat Pump
If E and Aux do not each have a wire connected, use a small piece of wire to connect them to each other.

Alternate Wiring (Heat Pump Only)
If labels do not match letters on the thermostat, check the chart below and connect to the terminal as shown here (see notes, below).

1. Leave metal jumper in place, connecting R and Rc terminals.
2. If your old thermostat had both V and VR wires, stop now and contact a qualified contractor for help.
3. If your old thermostat had separate O and B wires, wrap the B wire in electrical tape and do not connect.
4. If your old thermostat had Y1, W1, and W2 wires, stop now and contact a qualified contractor for help.
5. If there were separate wires on E and Aux, place both wires in the Aux/E terminal.

Install Batteries

Install Thermostat onto Wallplate
Install thermostat onto the wall plate on the wall.

Turn Power Back On
Turn the power back on to the heating/cooling system.

If your system type is…
If your system type is:

• Single-Stage Heat and Cool

Congratulations, you’re done!
If your system type is:

• Multistage Heat and Cool
• Heat Pump* without Backup Heat
• Heat Pump* with Backup Heat
• Heat Only
• Cool Only

Continue with Advanced Installation to match your thermostat to your system type.
*Heat Pump—an air conditioner that provides cooling in the summer, and also runs in reverse in the winter to provide heating. If you are not sure of your system type or if you have other questions, call us toll-free at 1-800-468-1502.
This thermostat works on 24 volt or 750 mV systems. It will NOT work on 120/240 Volt systems.

Advanced Installation

Enter System Setup
To enter the system setup, press and hold both the and FAN buttons until the display changes (approximately 5 seconds).

Changing Settings

1. Press the or button to change the setting.
2. Press NEXT to advance to the next function.
3. Press DONE to exit and save settings.

Gas, oil, or electric heating with
central air conditioning.
1. Heat pump: Outside compressor provides both heatings
and cooling without backup or auxiliary heat.
2..Heating only: Gas, oil or electric heating without central
air conditioning.
3. Heating only with fan: Gas, oil or electric heating
without central air conditioning. (Use this setting if you
could turn the fan on and off with a fan switch on your
old thermostat.)
4. Cool only: Central air conditioning only.
5. Heat pump: Outside compressor provides both heatings
and cooling with backup or auxiliary heating.
6. Heat/Cool Multiple Stages: Two heat stages (wires on
W and W2), two cooling stages (wires on Y and Y2).
7. Heat/Cool Multiple Stages: Two heat stages (wires on
W and W2), one cooling stage (wire on Y).
8. Heat/Cool Multiple Stages: One heat stage (wire on
W), two cooling stages (wires on Y and Y2).
2.| select whether the changeover valve is used in heating or cooling| 0. Cooling changeover valve: Use this setting if you connected a wire labeled “O” to the O/B W wire terminal.
1. Heating changeover valve: Use this setting if you
connected a wire labeled “B” to the O/B W wire terminal.
3| select your heating system and fan operation| 0. Gas or oil heat: Use this setting if you have a gas or oil
heating system (system controls fan operation).
1. Electric heat: Use this setting if you have an electric
heating system (thermostat controls fan operation).
---|---|---
5| select your heating system and optimize its operation| 5. Gas or oil furnace: Use this setting if you have a
standard gas or oil furnace that is less than 90%
efficient.
9. Electric furnace: Use this setting if you have any type
of electric heating system.
3. Hot water or high-efficiency furnace: Use this setting
if you have a hot water system or a gas furnace of
greater than 90% efficiency.
1. Gas/oil steam or gravity system: Use this setting if
you have a steam or gravity heat system.
6| select your Stage 2 heating system and  optimize its operation| 5. Gas or oil furnace: Use this setting if you have a standard gas or oil furnace that is less than 90% efficient.
9. Electric furnace: Use this setting if you have any type of electric heating system.
3 . Heat pump, hot water, or high-efficiency furnace:
Use this setting if you have a hot water system or a gas furnace of greater than 90% efficiency.
1. Gas/oil steam or gravity system: Use this setting if you have a steam or gravity heat system.
12| select Manual or Auto Changeover| 0. Manual Changeover: (Heat/Off/Cool)
1. Automatic Changeover: (Heat/Off/Cool/Auto) Automatically turns on heat or cool based on room temperature.
CAUTION: To avoid possible compressor damage, do not use Auto Changeover if the outside temperature drops below 50 ºF (10 ºC).
NOTE: The system maintains a minimum 3  ºF difference between heat and cool settings.
14| select Fahrenheit or Celsius temperature display| 0. Fahrenheit temperature display (°F)
1. Celsius temperature display (°C)
27| select maximum heat temperature setting| 40 – 90 Maximum heat temperature setting (°F) (4.5 to 31.5°C)
28| select minimum cool temperature setting| 50 – 99 Minimum cool temperature setting (°F) (10.5 to 37°C)

About your new thermostat

Your new Honeywell thermostat has been designed to give you many years of reliable service and easy-to-use, push-button climate control.

• The large, clear, backlit display is easy to read — even in the dark.
• Displays both room temperature and temperature settings.
• Removable battery holder for fast, easy replacement.
• Built-in compressor protection.

Thermostat controls

Display screen

In “Auto” mode (the most commonly used setting), the fan runs only when the heating or cooling system is on. If set to “On,” the fan runs continuously.

• Heat: The thermostat controls only the heating system.
• Cool: The thermostat controls only the cooling system.
• Auto: Thermostat automatically selects heating or cooling depending on the indoor temperature.
• Off: Heating and cooling systems are off.

Adjust the temperature

Press or adjust the temperature.
NOTE: Make sure the thermostat is set to the system you want to control (heat or cool).

Auto Changeover
Use this feature in climates where both air conditioning and heating are used on  the same day. When the system mode is in Auto, the thermostat automatically selects heating or cooling depending on the indoor temperature.
While in the Auto mode, if a schedule override takes place (temporarily or permanently) the thermostat will automatically adjust the cooling and heating settings to maintain a 3- degree separation between the cool and heat settings.
For example, if the heat temperature is raised to where it gets within 3-degrees of the cool setting, the display will show an up arrow next to “cool” to show the thermostat is  raising the cool setting up to maintain a 3-degree separation.
Press the Select Heat/Cool button to select between the heat and cool to view/ adjust either mode.

NOTICE: To avoid possible compressor damage, do not use Auto Changeover if the outside temperature drops below 50ºF (10ºC).

Built-in compressor protection

Battery replacement

Install fresh batteries immediately when REPLACE BATTERY begins flashing. The warning flashes about two months before the batteries are depleted. Replace batteries once a year, or when you will be away for more than a month.
If batteries are inserted within two minutes, the time and day will not have to be reset. All other settings are permanently stored in memory and do not require battery power.

Troubleshooting

If you have difficulty with your thermostat, please try the following suggestions. Most problems can be corrected quickly and easily.

Display is blank| • Make sure fresh AA alkaline batteries are correctly installed
---|---
Temperature settings do not change| Make sure heating and cooling temperatures are set to acceptable ranges:
• Heat: 40° to 90°F (4.5° to 32°C).
• Cool: 50° to 99°F (10° to 37°C).
Cannot change system setting to Cool| • Check Function 1: System Type to make sure it is set to match your heating
and cooling equipment
Fan does not turn on when heat is required| • Check Function 3: Heating Fan Control to make sure it is set to match your
heating equipment
Heating or cooling system does not respond| • Press SYSTEM button to set system to Heat. Make sure the temperature is
set higher than the Inside temperature.
• Press SYSTEM button to set system to Cool. Make sure the temperature is
set lower than the Inside temperature.
• Check circuit breaker and reset if necessary.
• Make sure power switch at heating & cooling system is on.
• Make sure furnace door is closed securely.
• Wait 5 minutes for the system to respond.
“Cool On” or “Heat On” is flashing| • Compressor protection feature is engaged. Wait 5 minutes for the system to
restart safely, without damage to the compressor.
Heat pump issues cool air in heat mode, or warm air in cool mode| • Check Function 2: Heat Pump Changeover Valve to make sure it is properly
configured for your system
Heating and cooling equipment running at the same time  (or heat does not turn off)| • Check Function 1: System Type to make sure it is set to match your heating
and cooling equipment.
• Grasp and pull thermostat away from wallplate. Check to make sure bare
wires are not touching each other.
Heating system is running in cool mode| • Check Function 1: System Type to make sure it is set to match your heating
and cooling equipment

For assistance with this product, please visit http://yourhome.honeywell.com or call Honeywell Customer Care toll-free at 1-800-468-1502.

1-year limited warranty

Honeywell warrants this product, excluding battery, to be free from defects in the workmanship or materials, under normal use and service, for a period of one (1) year from the  date of purchase by the consumer. If at any time during the warranty period the product is determined to be defective or malfunctions, Honeywell shall repair or replace it
(at Honeywell’s option).
If the product is defective, (i) return it, with a bill of sale or other dated proof of purchase, to the place from which you purchased it; or
(ii) call Honeywell Customer Care at 1-800-468-1502. Customer Care will make the determination whether the product should be returned to the following address:
Honeywell Return Goods, Dock 4 MN10-3860, 1985 Douglas Dr. N., Golden Valley, MN 55422, or whether a replacement product can be sent to you. 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 which 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 Honeywell Customer Relations, 1985 Douglas Dr, Golden Valley, MN 55422 or call 1-800-468-1502.

Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
yourhome.honeywell.com
® U.S. Registered Trademark.
© 2015 Honeywell International Inc.
33-00139ES—01 M.S. 08-15
Printed in U.S.A.

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