Honeywell Thermostat AC Not Turning On: Easily Troubleshoot

Filed in How-To Guide by on December 7, 2022 0 Comments

Honeywell Thermostat AC Not Turning On: Fixing Honeywell Thermostat Do not Turn On AC issue. Your Honeywell thermostat may occasionally fail to switch on your air conditioning. Resetting your thermostat is the most straightforward solution. You can also try changing your batteries, inspecting your wiring, or cleaning the air filter connected to your Honeywell Thermostat.


How can I fix a Honeywell thermostat that won’t work?

How to Fix a Malfunctioning Honeywell Thermostat

  • The thermostat’s cables must all be disconnected.
  • Take the gadget out of the wall plate.
  • Five minutes should pass once the batteries are removed.
  • Both the batteries and the cables should be replaced.
  • Wait five minutes after turning on the system.


Does a Honeywell thermostat have a reset button?

Set back to factory defaults

The Honeywell T5+ / T5 / T6 Pro Series Thermostats should be reset using the following procedures: Make sure the gadget is turned on (it should be on). Press and hold the menu button for five seconds. As you continue to the left, halt when you see “Reset.”


How To Tell if your Thermostat  is Bad

Honeywell Thermostat Not Working

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What Thermostat Model Do I Have?

Checking the thermostat ID card is the quickest way to determine the model of your thermostat.

If you don’t have the product ID card, detaching the device from the wall plate should reveal it.

The majority of models are easily removable from walls. Flip it over after detaching it to reveal the model number printed on the case’s rear.

The letters TH, T, RTH, RCHT, CT, TL, or RLV come before the number.


Common Solutions for Honeywell Thermostat AC Not Turning On

Now that you know the Honeywell thermostat model you are using, let me walk you through some basic ways to fix a thermostat that isn’t cooling.


Reset the Thermostat to Factory Settings

Depending on the model you have, several procedures may be required to reset your Honeywell thermostat.

Follow the instructions below and scroll down to the model that you own.


4000 series by Honeywell

Press and hold the “Program” option after making sure the device is ON.

Press and hold the reset button for one to two seconds while using a paperclip or other pointed object, and then let go of the “Program” button.


6000 series by Honeywell

Press and hold the “Fan” button, followed by the “Up” arrow button, while your device is “ON,” holding these buttons for about 5 seconds before letting go.

When the number on the display panel changes to “39,” press the button in the bottom left corner.

Then click “Done” after pressing the “Down” arrow button until you see “0.”
Now that the thermostat has been adjusted.


7000 series by Honeywell:

Before turning off the power to your gadget, turn off the thermostat. The thermostat should now be taken out of the wall plate.

Two AAA Alkaline batteries are included. Take them out, then put them back in for about five seconds going the other way.

Put the batteries in the proper order now, and the display should turn on. After mounting your thermostat on the wall plate, turn on the power.


Family Honeywell Lyric T

To reset, tap the “Menu” button and scroll down to the bottom of the screen. To finish the reset, tap “Select” and select “Yes.”
If you tap “No,” you will be taken back to the reset sub-menu.


Series 8000 by Honeywell

Press and hold the blank button in the center for 5 seconds after selecting “System” on the screen. Select “Reset to factory settings” at this time. The thermostat has been reset at this time.


Series 9000 by Honeywell

Click the “Menu” button, then select “Preferences.” To “Restore to factory default,” scroll down and select “Yes.”

Please be aware that when you reset your thermostat, you will need to establish your schedules regardless of the model and adjust the clocks.

If you haven’t replaced batteries in a while, do it now (selected models only)

Your thermostat’s batteries need to be replaced (if your model uses batteries).

  • Make sure the electricity is “Off” by going to the circuit breaker.
  • Your thermostat must be removed from the wall plate.
  • Place the new batteries in and remove the old ones.
  • Reconnect the electricity to “On” and then secure your thermostat to the wall plate.


Check For Damage In Connections And Wiring

Remove the thermostat face or body to reveal the wiring and check to see if it is secure.

A white wire and a red wire are present. Your thermostat should turn “On” once these are connected.

If your heating system activates when the wires are connected, the thermostat is at fault.

First, make sure that your thermostat is set higher than the ambient temperature.

The thermostat wires may be faulty if connecting the red and white wires does not solve the problem.

Given how risky manipulating the AC mains supply is, it is preferable that you do not test the integrity of the thermostat wires yourself. Instead, give a pro a call and ask for assistance.


If the air filter is clogged, replace it.

Your air conditioner will have issues if your air filter is blocked since it will be impossible for air to flow through the vents. Your AC may consequently leak or work too hard.

Checking and cleaning your air filters on a regular basis is necessary to avoid long-term harm to your AC.

This increases their efficiency and assures a longer lifespan for them.

Every few months or whenever you notice anything gray or ashy-looking on the duct side of your filter, you should usually clean the air filters.


If nothing else works, speak to Honeywell Support.

It is preferable to get in touch with Honeywell Support if you are certain that none of the aforementioned factors is the root of the problem with your Honeywell thermostat.

Being unable to control your home’s temperature can be upsetting, particularly on a hot day.

But with these straightforward fixes, your air conditioner will be operational in no time.

You may always contact Honeywell support if you couldn’t figure out the problem on your own.

Additionally, I want to caution you from fiddling around too much with your home’s wiring because your safety should always come first!


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