Honeywell RTH8500 Series Programmable Thermostat Guide

Honeywell RTH8500 Series Programmable Thermostat

Removing your old thermostat

1. Turn power OFF.
   To protect yourself and your equipment, turn off the power at the breaker box or switch that controls your heating/cooling system.
2. Check that your system is off.
   Change the temperature on your old thermostat. If you don’t hear the system turn on within 5 minutes, the power is off. Note: If you have a digital thermostat that has a blank display, skip this step.

If you’re looking for simpler Honeywell models, you can check the Honeywell RTH2410 thermostat user guide or the Honeywell RTH2300 user guide.

1. Remove the old thermostat’s faceplate.
   On most thermostats, you can take off the faceplate by grasping and gently pulling. Some thermostats may have screws, buttons, or clasps. Do not remove any wires from your thermostat at this time!
2. Make sure there are no 120/240V wires.
   Do you have thick black wires with wire nuts?
   Is your thermostat 120V or higher? If you answered yes to either of these questions, you have a line voltage system, and the thermostat will not work. If you are unsure, visit: honeywellhome.com/support
3. Take a picture of how your wiring looks right now.
   Be sure to include the letters next to the terminals where the wires are inserted. This will be a helpful reference when wiring your thermostat. Tip: If the color of your wires has faded or if 2 terminals have the same wire color, use the wire labels provided in the package to label each wire.
4. Record if you have wires in the following terminals
   Do not include jumpers as part of your count. The thermostat does not need jumpers.
5. Write down the color of the wires.
   Check the wires that are connected to the terminals. Next to the check mark, write down the color of the wire. Do not include jumpers as part of your count.
   Check all that apply (Not all will apply)
   
   The RTH8500 thermostat does not support S or U terminals.
   If there are wires in terminals that are not listed, you will need additional wiring support. Visit honeywellhome.com/support to find out if the thermostat will work for you.
6. Disconnect the wires and remove the old wall plate
   Use a screwdriver to release wires from terminals. Then, use a wire label to identify each wire as it’s disconnected. The letter on the wire label should match the letter on the terminal. Tip: To prevent wires from falling back into the wall, wrap the wires around a pencil.
7. Bundle and insert wires through the UWP
   Pull open the UWP and insert the bundle of wires through the back of the UWP. Make sure at least 1/4-inch of each wire is exposed for easy insertion into the wire terminals.
8. Insert the wall anchors.
   It is recommended that you use the wall anchors included in the box to mount your thermostat.
   You can use the UWP to mark where you want to place the wall anchors.
   a) Level the wall plate. b) Mark the location of the wall anchors using a pencil. c) Drill the holes. d) Insert wall anchors. e) Make sure anchors are flush with the wall. Tip: If your box contains red anchors, drill 7/32” holes. If your box contains yellow anchors, drill 3/16” holes
9. Set R-switch position and insert R-wire or wires
   Set the R-switch up or down based on your wiring notes in Step 7.
   Insert wires into the inner holes of the terminals on the UWP. The tabs will stay down once the wire is inserted
10. Connect wires from Step 7
    Depress the tabs to put the wires into the inner holes of their corresponding terminals on the UWP (one wire per terminal) until it is firmly in place. Gently tug on the wires to verify they are secure. Tip: If you need to release the wires again, push down the terminal tabs on the sides of the UWP.
11. Mount the UWP and close the door.
    Mount the UWP using the provided screws. Install all three screws into the wall anchors for a secure fit on your wall. Close the door after you’re finished.
12. Confirm wiring matches the snapshot
    Please confirm wiring matches terminals from the photo you took in Step 5.
13. Install batteries
    Insert three AA alkaline batteries in the back of the thermostat as shown. NOTE: The RTH8500 thermostat works in battery mode or normal power mode if a C-wire is available.
14. Attach your thermostat
    Align the thermostat with the UWP and firmly snap it into place.
15. Turn your power ON.
    Done. Turn on the power at the breaker box or switch that controls the heating/ cooling system.
16. Return to the thermostat Return to the thermostat.
    Confirm the screen shows START SETUP. OFF Switch M39446 If your thermostat does not show START SETUP, please contact Honeywell Home support.

For advanced touchscreen models, see the Honeywell TH9320WF installation guide.

1. Start setup
   Touch START SETUP to begin
2. Navigate and edit setup options
   Use the or to navigate through all the setup options. To see a list of all setup options, go to pages 9-10. To edit an option, touch Edit or touch the text area. The value is now blinking. Use or to select the correct value. Touch Done or touch the text area once the correct value is selected
3. Finish setup
   Touch until you see FINISH SETUP. Touch Select or touch the text area.
4. Set time and date. Set daylight saving time if you are in an area that follows daylight saving time. Set date, clock format, and time on the next screens.
   
5. Your thermostat is now set up. Refer to page 8 for more information about basic operation. M36181A Done Cancel M36277 Select No M37366 Yes Back

Key features

System Setup options

To access all system options in the table below, press and hold MENU for 5 seconds. To touch or scroll through the list.

NOTE: Once you have cycled through all of the System Setup numbers, Done is displayed. Press Select to save and exit.

Smart Response® Technology

This feature allows the thermostat to “learn” how long the furnace and air conditioner take to reach programmed temperature settings, so the temperature is reached at the time you set. For example: Set the Wake time to 6 am, and the temperature to 70°. The heat will come on before 6 am, so the temperature is 70° by the time you wake at 6. The message “Recovery” is displayed when the system is activated before a scheduled period.

If you prefer smart control, the Honeywell T9 Smart Thermostat guide might be a better fit.

Battery replacement

Batteries are required to provide power when a common wire is not used. Batteries are recommended to provide backup power if the common wire is used. Install fresh batteries immediately when the low battery icon appears. The icon appears about two months before the batteries are depleted. Even if the low battery icon does not appear, you should replace batteries once a year, or before leaving home 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.

NOTE: When replacing batteries, alkaline batteries are recommended.

Setting the time and date

Setting the time

1. Touch Menu on the thermostat home screen.
2. Touch the or arrows until you see CLOCK, then touch Select.
3. Touch the or arrows until you see SET TIME, then touch Select.
4. Press or to set the time (or press and hold the buttons to move more quickly). Touch Done when finished.
5. Set clock format (12 hours or 24 hours) and daylight saving time in the same CLOCK sub-menu.

Setting the date

1. Touch Menu on the thermostat home screen.
2. Touch the or arrows until you see DATE, then touch Select.
3. Touch or tap the month, then touch Select to confirm.
4. Continue to set the day and year in the same way. Touch Select to save your changes.

Choosing Fahrenheit or Celsius

To select a temperature scale, follow the steps below.

1. Touch Menu on the thermostat home screen.
2. Touch the or arrows until you see TEMP SCALE, then touch Select.
3. Touch the or arrows to select FAHRENHEIT or CELSIUS, then touch Done to save your changes.
4. Touch Back to return to the thermostat home screen.

Alerts and maintenance reminders

1. Touch Menu on the thermostat home screen, then you’ll see the ALERTS submenu. (The ALERTS sub-menu will only be available when there’s an active alert.)
2. Touch Select to view the alert. A 3-digit alert code will appear by the thermostat’s clock, and a description of the alert will scroll on the screen.
3. If the alert is non-critical, you’ll have the option to Snooze or Dismiss it. If you have multiple alerts, touch the arrows to page through the list of active alerts and follow steps 1 and 2 above.
   To see what each 3-digit alert code means and the action you should take, refer to the chart below.

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 properly installed (see page 6). If powered by common (C-wire), verify circuit breaker and furnace switch are turned on. Verify the furnace door is securely closed.

Cannot change the system setting to Cool

Check System Setup Option 220 to make sure the Honeywell RTH8500 Series options are set to either 1 or 2 (see page 9).

The fan does not turn on when heat is required

Check System Setup Option 205 to make sure it is set to match your heating equipment (see page 9).

The heating system is running in cool mode

Check System Setup Option 200 or 218 to make sure it is set to match your heating and cooling equipment (see page 9).

The heating or cooling system does not respond

Press the System to set the system to Heat. Make sure the temperature is set higher than the Inside temperature. Press the System to set the system to Cool. Make sure the temperature is set lower than the Inside temperature. Check the circuit breaker and reset if necessary. Make sure the power switch on the heating & cooling system is on. Make sure the furnace Honeywell RTH8500 Series door is closed securely. Wait 5 minutes for the system to respond.

Still facing issues? You can also check the Honeywell RTH7500 troubleshooting guide for similar solutions.

Heat On / Cool On flashing on the screen

The 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 System Setup Option 200 or 218 to make sure it is set to match your heating and cooling equipment (see page 9).

Aux heat runs in cooling

For heat pump systems, verify that there is no air attached to W on UWP systems. See “Wiring—heat pump” on page 15.

Cool runs with a call for heat

For heat pump systems, verify that there is no wire attached to W on UWP systems. See “Wiring—heat pump” on page 15.

1-year limited warranty

Resideo warrants this product, excluding battery, to Honeywell RTH8500 Series be free from defects in workmanship or materials, under normal use and service, for one (1) year from the date of first purchase by the original purchaser. If at any time during the warranty period the product is determined to be defective due to workmanship or materials, Resideo shall repair or replace it (at Resideo’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 Resideo Customer Care at 1-800-468-1502. Customer Care will make the determination whether the product should be returned to Honeywell RTH8500 Series the following address: Resideo Return Goods, 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 Resideo that the defect was caused by damage that Honeywell RTH8500 Series occurred while the product was in the possession of a consumer. Resideo’s sole responsibility shall be to repair or replace the product within the terms stated above.

RESIDEO 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 RESIDEO MAKES ON THIS PRODUCT. THE DURATION OF ANY IMPLIED Honeywell RTH8500 Series 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 Resideo Customer Care, 1985 Douglas Dr, Golden Valley, MN 55422, or call 1-800-468-1502

CAUTION: ELECTRICAL HAZARD. Can cause electrishock or damageaequipmentntte. Disconnect power before beginning installation.

Electrical Ratings

Customer assistance

For assistance with this product, please visit Honeywellhome.com/suppo.rt