Honeywell Thermostat Flashing Cool On: How To Troubleshoot

Going home to an extremely cold or warm house is the last thing that every homeowner would like to experience. However, this is a common phenomenon for those homeowners who live in areas that experience extreme temperatures. To keep such inconveniences at bay, most people have now invested in thermostats and HVACs systems.

Honeywell is one of the best brands when it comes to the manufacture of smart home devices such as thermostats, air purifiers, heaters, fans, air monitors, and many more. If you have a Honeywell thermostat, you can readily control it remotely through a touch of a button or a voice command. Just like any other device, the Honeywell thermostat is not immune to some diagnostic issues. For instance, you may notice that your thermostat is flashing a ‘Cool On’ indicator every now and then.

If you have never experienced this issue in the past, you are likely to freak out. However, this is perfectly normal with such devices. In this article, we shall take an in-depth look at why Honeywell thermostat flashing cool on, how to troubleshoot that problem, alongside other related ideas:

What Does The Display ‘Cool On’ Mean?

Before we delve into how to troubleshoot this diagnostic issue, it is imperative that we demystify what this display means so that you can know it better. Typically, this indicator is one of the many operations or system modes that are regulated by the thermostat. Just like the ‘Heat On’ display, this one simply tells you that your device has started to work hand-in-hand with the HVAC system.

It is important to note that the ‘Cool on’ display is also known as the snowflake icon. With this display in place, be sure that your device is in delay mode. This mode is usually activated in order to protect the HVAC system from short cycling. If this mode is on, it shows that the thermostat has actually turned on the AC cooling of your home.

Ideally, this display should not last for long. In fact, it should only keep flashing ‘Cool on’ for 5 minutes and then switch off. However, if the flashing does not stop after the above-mentioned stipulated time period, then there might be an underlying problem that needs urgent attention.

Why My Honeywell Thermostat Flashing Cool On: How To Troubleshoot The Problem

Since we have established that the Honeywell thermostat should only display the ‘Cool on’ for 5 minutes, if it keeps flashing this display beyond the above-mentioned time period, chances are that there is a problem with your devices.

In fact, if the indicator keeps flashing for more than 5 minutes and you do not feel any cool air in your house, that’s a red flag and you need to troubleshoot the diagnostic issue immediately. Here are some of the reasons why the Honeywell thermostat keeps on flashing the Cool on display for more than 5 minutes:

1) Your device’s battery is low

One of the main reasons why the Honeywell thermostat may keep flashing the ‘Cool on’ is because your device’s battery might be low and needs to be replaced. Since the device needs a battery to be powered on, it will not turn on the AC of your house and thus will prevent you from getting the cool air in your house.

Although the new models usually have separate indicators that help you know your device’s battery is low, the old models normally flash the ‘Cool on’ in order to inform you that your device’s battery is low and needs to be replaced.

To solve this problem, you need to purchase a new set of batteries for your device. However, before you rush to purchase these batteries, you should take a closer look at the device’s display and establish if the ‘battery low’ light is still flashing or not.

If the device is displaying this warning, know that you have about 2 months to replace the battery. Therefore, instead of waiting for two months for you to replace the batteries, you can replace them on the go and see if the problem will persist or not.

2) The device’s compressor had been restarted within a short span of time

Besides the battery issue, the thermostat may start flashing the ‘Cool on’ if at you have tried to change the temperature manually. By doing so, you will be forcing the compressor to restart.

Such usually happens when you want to change the room’s temperature from hot to cool or from cool to hot. Although such random changes in temperature might be convenient for the time being, they can affect the HVAC system in one way or another.

If you had tried to make such sudden temperature changes, give your device about 10 minutes and see if the ‘Cool on’ display will switch off or not. Within those 10 minutes, be sure that your device will recover automatically and start working optimally. If the 10 minutes are over and the ‘Cool on’ is still on your device’s display, consider taking the next alternative.

3) Reduce the room’s temperature to the lowest levels

In case you have waited for 10 minutes and the Honeywell thermostat is still flashing the ‘Cool on’ indicator, you can consider lowering the temperature and wait for about 10 minutes. Here you should adjust the controller setting and establish whether the cooling will work or not. As you set the temperature to the lowest possible levels, ensure that the fan’s setting is on the ‘Auto’ mode and that the device is on ‘Cool’ mode.

If there is no noticeable changes in temperature after 10 minutes, then there is an underlying problem that needs to be diagnosed on the go. Read on to know about other issues that might cause the Honeywell thermostat to keep on flashing ‘Cool on’ for more than 10 minutes.

4) Your thermostat is in the setup mode or its clock is not set

If there was a power outage or a blackout in your home, chances are that the thermostat will shift to the setup mode. This can make the device start blinking the ‘Cool on’ indicator. Better still, consider checking the timing on your thermostat. In case it is not set or wrong, ensure that you set it correctly. This is because your device might start blinking the ‘Cool on’ indicator if its timing is not well set.

5) The furnace, AC unit, or air fan might not be getting the much-needed power

The AC unit, furnace, and air fan are some of the HVAC components that need power for them to work flawlessly. To establish whether these components are getting the much-needed power, you should take time to check vital areas such as the connections leading to these components, the sockets, and power supplies, among other vital elements. Ideally, you should ensure that they are well connected with the respective choices turned on.

Besides the power supply, ensure that the doors are well closed and that there are no unscrewed components. In case there are some loose components, secure them in place. If you have a circuit breaker, check it to ensure that it is not turned off. You can even try to switch it off and then on and see if the problem will persist or not.

Finally, you can check the blow fuses and see if they have blown or not. A voltmeter can help you establish whether the blow fuses have blown or not. In case the fuses have blown, you might need to replace them on the go.

6) The AC filter might need to be replaced

If the other HVAC components are working optimally and still the device keeps blinking the ‘Cool on’ indicator on its display, chances are that the indoor filter requires to be replaced. In fact, if the AC filters are faulty, you may not be able to enjoy the much-needed cooling effect in your home. Besides this, the thermostat and the air quality might be adversely affected. The power bill may skyrocket as well.

To keep these problems at bay, you should consider replacing the AC filter after every 3 months. This is because this component usually gets clogged during the summer months. Dust and dirt might clog it thereby affecting the functionality of the AC unit. To put it into perspective, the AC has to work triple harder for it to cool your house.

Consequently, this mounts pressure on the compressor of the HVAC system and other related components. When it comes to the thermostat, it may not even be able to turn on the AC if all the filters are clogged. Therefore, you may experience a number of issues when it comes to temperature regulation in your home. However, once you replace the AC filters, you will be able to avert such issues.

7) The AC coils are dirty

Just like the AC filters, the AC coils can get dirty. Although these components do not get dirty frequently, sometimes, they can accumulate dirt if they have been in use for a couple of months.

If they are clogged, airflow will be hampered and thus affect the way cooling and heating processes take place in your house. In fact, a clogged AC coil will not be able to absorb heat and cool the air as desired.

To keep this problem at bay, you should ensure that you clean the AC coils regularly. By cleaning these components, you will be able to eliminate the dirt and dust that might affect the heating and cooling system of your home. When cleaning the coils, you should first switch off the system and then clean them thoroughly. 

Besides this, clean the areas around the AC coils so that they will not get clogged in the near future. For optimal results, ensure that you place your unit in a spacious room that is devoid of furniture, plants, and other elements that might interfere with airflow.

8) There is a malicious bug or glitch that has affected your device

Your Honeywell thermostat is not immune to a technical problems such as malicious bug attacks. Other times, there might be a glitch that is making it blink the ‘Cool on’ indicator every now and then. If this is the case, you should consider resetting the device. By resetting the device, you will get rid of these bugs on the go.

By resetting the device, you will take it back to the default settings. All the data that was saved here will be erased. Generally, it will have the settings it had when you purchased it from the manufacturer or store near you. If you want to reset your device, you should be keen to check its model first.

In case the device is powered through C-wire, you might be required to disconnect it from the power supply of your home first. By doing so, you will be safe from electrocution. Thereafter, locate the Menu button and then press it for a few seconds and then release it. Once you release it, the device will reset successfully. You can now configure the device to the previous settings.

9) Check the user’s manual

Just like any other device, the Honeywell thermostat comes with a user manual that can help you to troubleshoot a number of diagnostic issues. The good news is that these instructions are usually well-outlined and are always related to a particular model. If encounter glitches such as a ‘Cool on’ indicator, you can check your manual and see if you will get a solution to solve it. In case you do not have the physical manual, you can check it on the internet and you will get a soft copy that will help you out.

10) Contact the Honeywell Customer Support team

If all the above-mentioned ideas fail to work, consider contacting the Honeywell customer support team. The good news is that this team is available on phone or through the website. Once you reach out to an agent on the other end, narrate your story in detail. The agent or professional from the other end will ask you a couple of questions and then offer meaningful help to you. From sending a professional near you to check your device to ask you to bring the device for further checkups, there is a myriad of solutions this team can offer to you.

Final Words

As a first-time thermostat owner, figuring out the ‘Cool on’ indicator might be a tall order. You may panic or think that your device is damaged entirely. However, this is not always the case as this issue can be diagnosed by following the above-mentioned ideas. From checking the battery status of the device to checking the user’s manual, there are a plethora of solutions that can help you get started. If the worst comes to the worst, contact the Honeywell customer support team for further guidance and support.

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