Honeywell Thermostat Not Working: Reasons And Troubleshooting

When the battery ran out of juice, I replaced them as usual but then I noticed it’s doing nothing! I kept wondering why is my Honeywell thermostat not working?

As the warranty period ran out and I was on the verge of getting a new one, I just wanted to give it a last try. And it worked!

I admit I had to spend plenty of time finding the trouble and fixing it. So, in this article, I will talk about all the reasons why it stops working and how to troubleshoot it. Stay with me.

Troubleshooting Honeywell Thermostat Issues

honeywell thermostat not working

Before you rush to the solution, it’s important that you identify the root cause of the problem. Only then you can troubleshoot the problem effectively and without wasting much time.

I will start with the simple reasons and solutions first. So, here are some probable causes and troubleshooting tips you can apply:

  • Honeywell Thermostat Display Problems

I think we all have faced this problem. Yes, along with other problems, a blank thermostat screen is frustrating too and it happens a lot when your thermostat has a digital display.

Usually, the display problem is linked to the power. Meaning, most of the time it will have display problems with the batteries are running out of juice.

When the batteries are dead or even low on juice, you will notice problems like fading digits, flashing symbols, and so on. Just insert some fresh batteries to fix the problem.

But it will a little bit difficult to inspect if your system is hardwired. You can still do it. Just take a deep breath and concentrate.

You need to look for tripped breaker, loose wiring, or open furnace door to fix the blank screen problem first. So, make sure the electrical breakers are not tripped.

If the HVAC system’s access door is not closed all the way, the digital display will give you a blank screen too. Usually, there is an activation switch that activates the system when the door is completely closed.

If the door is not closed, it will cut the power to the system. So, make sure the door is all the way closed.

And lastly, if are confident, remove the cover and check the wiring. Refer to the user manual if you need to. If you are not comfortable dealing with electrical wiring, hire a professional to do so.

  • Malfunctioning Temperature Sensor

The thermostat may not work even if the display is working. It happens sometimes when your home will feel too hot or cold than whatever it’s displaying on the screen.

This happens when you have a malfunctioning temperature sensor!

You can test it by using a thermometer. Measure the thermostat’s location temperature using the thermometer and it does not match up, you have a faulty sensor.

Most of the time you will get away with it replacing the sensor. However, the same situation may arise due to other reasons like incorrect jumper settings, incorrect day & time settings, loose wires, etc. too!

Have a good look at them if replacing the sensor does not fix the problem and make necessary adjustments.

  • Honeywell Thermostat Won’t Turn on Heat

I don’t know about you but when my thermostat is not turning on the heat, it becomes more painful and frustrating than when it’s not cooling the home.

I mean I could take measures to cool down the house running fans and other ways easily. But what about the heat during the chilling winter?

How long you can be under the blanket? Luckily, the reasons are pretty much the same when the thermostat is not cooling the home or turning on the heat.

Before you inspect anything, make sure the furnace is on. Since the tripped circuit breaker is the most common reason for the heat functioning not working, this is where you should check next.

If you can feel the air, then the furnace fan is working and you should refer to the manual for further troubleshooting.

Call the service technician if nothing works.

Like not turning on the heat, you may face the problem where your thermostat may not turn off the heat as well. It may happen due to a broken switch, bad wiring, or when there is something seriously wrong with the thermostat.

  • Honeywell Thermostat Won’t Turn On AC

Honeywell Thermostat Won’t Turn on Heat I don’t know about you but when my thermostat is not turning on the heat, it becomes more painful and frustrating than when it’s not cooling the home. I mean I could take measures to cool down the house running fans and other ways easily. But what about the heat during the chilling winter? How long you can be under the blanket? Luckily, the reasons are pretty much the same when the thermostat is not cooling the home or turning on the heat. Before you inspect anything, make sure the furnace is on. Since the tripped circuit breaker is the most common reason for the heat functioning not working, this is where you should check next. If you can feel the air, then the furnace fan is working and you should refer to the manual for further troubleshooting. Call the service technician if nothing works. Like not turning on the heat, you may face the problem where your thermostat may not turn off the heat as well. It may happen due to a broken switch, bad wiring, or when there is something seriously wrong with the thermostat.

Let’s dive into the more serious problem. It’s hot summer and the central system is not cooling down your home. Nothing gets frustrating than that!

Let’s start by simply troubleshooting. First, make sure it’s set to ‘Cool’ mode and more importantly it’s ‘ON’. And ensure that the panels are closed.

Even if you set the system ON, your air conditioner won’ turn on unless the temperature is set below the temperature of the room. So, set the temperature below the room temperature.

If the thermostat is not working even if everything checks out, have a look at the display. Is there any flashing icon? If so, it will work within just 5 minutes because right now, your thermostat is on the Delay More for the time being.

Let’s say it’s still not cooling the house even if everything checks out and the breaker is not tripped, there may be a problem with the air conditioning unit.

If you are not confident to inspect your AC unit, hire an experienced AC technician.

  • Honeywell Thermostat Not Communicating

Your smart thermostat may experience all the problems listed above. Additionally, it may face other issues that are completely unique to those smart thermostats.

But 90% of the time, it may face a connectivity issue. This also happens because most of the time people install the wrong mobile apps.

Honeywell has several models of smart thermostats like T-Series and Round Smart Thermostats. For that two series, you need the Honeywell Home App.

But if you have FocusPRO, Prestige, or VisionPRO model, you need their Honeywell Total Connect Comfort Application. Both of the apps are available on the app store and Google Play store.

If it’s not connecting even if you have the correct app installed, it’s highly recommended to read the official documentation of the app you have installed.

Try to restart the router and your phone. If that does not fix the connectivity problem, uninstall the app and re-install it. To my experience, you have a 90% plus success rate to fix this problem this way!

  • Faulty Installation of Honeywell Thermostat

I admit installation of the Honeywell thermostat is easy. So, not everyone is interested to pay a large fee to a professional HVAC technician.

Some homeowners are handymen themselves or they call their relatives to deal with their thermostat issues. To be frank, there is nothing wrong with it.

But improper installation may lead to poor performance of your unit. Not just the amateurs, anyone can make such simple mistakes! So, pay attention to this part to understand why your thermostat may not be working.

First of all, look at the location of the thermostat where you have installed it. If it’s nearby the window, air vent, or kitchen, it will give you the wrong reading of the temperature.

You need to pick an installation location where it won’t get any direct sunlight in addition to avoiding those above-mentioned spots.

Another crucial factor in proper installation is that your thermostat has to be level to perform better. There is a mercury switch if you own an old thermostat.

Your thermostat relies on that switch that has to be completely level.

Even if it’s a few degrees off, it will give you the wrong temperature reading along with other problems like a short cycle.

If it’s not totally level, your air conditioner or heating will turn on or off more frequently than you want. But it can be easily fixed with a screwdriver and a level.

Just detach the thermostat from the wall, level it, and reattach it, and you are done!

  • HVAC System Is Not Work

A malfunctioning thermostat may make you think there is something wrong with your HVAC system. Plenty of reasons may contribute to this problem.

You need to start by checking the usual suspects like a tripped breaker or a blown fuse. Also, check whether there is a lack of power and if so, replace the batteries.

If it does not solve the problem, you need to take a look inside of the thermostat to check whether it’s dirty or not. So, first shut off the breaker and remove the cover.

Does it look dirty inside?

If so, that may also affect the functionality of your thermostat. Use a soft artist brush or canned air to remove the dirt or any accumulated grime.

While it’s open, look for any loose wiring or screws and tighten them up if necessary.

  • Room Temperature & Thermostat Mismatch

room temperature & thermostat mismatch

This happens a lot when you have a non-digital Honeywell thermostat. A little jarring bump can throw it off level and lead to such a mismatch between the thermostat and your room temperature.

However, if you have a carpenter’s level, it’s easy to fix. Just place the level above the thermostat and make necessary adjustments until it’s level again.

Sometimes the frozen anticipator is responsible if you have a mechanical thermostat. You need to un-stuck it and you can do so by locating the arm attached to the round dial and simply pushing it gently in either direction.

Your digital Honeywell thermostat may not work properly even if the screen is okay but the time-of-day and day-of-week are incorrectly set. This mainly happens after a power outage.

Yes, the battery should be able to keep the clock settings right but it does not happen always. So, the first thing you need to check whether the time and date are correct or not. If not, set the right settings.

If you have an electronic programmable thermostat, the wrong day and time will prevent it to function properly too. In that case, you need to set the right day and time.

You can take help from the manual in this regard.

How To Troubleshoot Analog Honeywell Thermostats?

I don’t know about you, but to me, older Honeywell thermostats with dial features are highly dependable. So, if you have one of them, here is a troubleshooting guide for you!

You need to first identify whether the COOL feature is working or not. To do so, set the fan switch to auto and the switch at the top of your thermostat to COOL.

Turn the dial to the lowest setting like 60℉ and wait for 5 minutes. If the air conditioner unit kicks in, the COOL feature is functioning right.

Now, you need to check the HEAT feature. So, turn your thermostat to the HEAT position and set the temperature as high as 80℉. Let your furnace activate. Just wait 5 minutes.

If the furnace kicks in after 5 minutes, the HEAT feature is okay. But if none of the COOL or HEAT feature does not work, there is a simple fix for your analog thermostat.

Remove the cover. Now, you need to make sure the small colored wires are properly connected. You can refer to your manual but restoring the connection of the low-voltage wires should solve the problem!

Frequently Asked Questions (FAQs)

What is the reset button on a thermostat for?

Answer: It’s basically there to troubleshoot general problems just like your smartphone. However, you can also use this if you are sure you won’t be home for a whole day.

In such a case, you can set it to the very lowest when the house is empty and reset it when you are home again.

Does the Honeywell thermostat have a reset button?

Answer: Yes. But you need to find the ‘Reset To Factory Settings’ option first. So, click on the ‘SYSTEM’ and hold the center button for some settings to get to the option.

Why is my thermostat not working?

Answer: There are several reasons why it may not work. Start pinpointing the problem like batteries run out of juice, tripped breaker, or blown fuse. If you are confident, you can take off its cover and check the inner components.

How do I reconnect my Honeywell thermostat?

Answer: To connect your thermostat to your home Wi-Fi network, make sure the Wi-Fi router is ON and broadcasting. If it’s not, restart your router and the thermostat should connect automatically.

Final Thoughts

Still wondering why is your Honeywell thermostat not working after the battery change? You should not feel bad about it as it happens more often.

Rather, try to pinpoint the problem first as I have shown above. Then troubleshoot the problem as I said. If nothing works, call your nearby service center.

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