Honeywell Pro Series Thermostat Cool on Flashing – Here’s What You Can Do

Electrical appliances are always bought at risk. No matter how long the product is on warranty, the customers are supposed to stay attentive. Some devices do not work appropriately, whereas some stop working suddenly and must be worked out immediately. People purchase thermostats to maintain their home temperature and keep the place warm or cold based on their requirements. It gets annoying when the thermostats do not work, especially in the hot weather. You return from work to relax at home, but your thermostat is not ready to provide cool air

If you have the Honeywell thermostat and it starts showing you the cool on flash constantly, this means that there is some problem. Even though this issue occurs commonly and is nothing major, you should still work out the issue before it gets completely damaged. 


When your thermostat generates the ‘cool on’ message, it’s processing and will give out cool air, which is normal if it keeps flashing for approximately 5 to 8 minutes. Still, an increase in time indicates that the thermostat has evolved some problems. This happens mainly when the previous battery in the thermostat has stopped working, and it requires fresh batteries to operate. The flash determines the need for a new battery. 


This also happens when the mode of the system changes internally. Generally, it would be best if you gave a break to your device between switching it off and switching it on again. Due to immediate on and off, the device does not proceed the same way as it shifts into a delay mode. 


You can consider following these steps to solve the issue when the Honeywell Pro series thermostat cool on flashing begins to happen.

Inspect The Electricity Supply

Before trying out any other way, it is essential to inspect your electrical board first. Since the thermostats require higher volts and operate on considerable energy, it is necessary to check whether they are getting the proper supply. Check all fuses and meters to ensure the power is responding correctly. 

Identify The Accurate Temperature Mode

The thermostat offers different modes to switch between. If you want to opt for a cool temperature, then make sure to select the cooling mode. Also, check the temperature, set the fan’s speed, and adjust the timer to ensure it’s working correctly. Remember not to change the modes instantly and start the thermostat again if it begins flashing. 

Make Sure To Modify The Setting Of The Thermostat

If you cannot operate the thermostat yourself, then seek help from the instruction book that comes along. Figure out the function of each symbol and mode and then change the settings. Different methods require different locations. 

For cooling mode, you should adjust the temperature to a lower scale, and the fan speed should be auto. You can also change the fan speed to turbo for a more cooling effect. Similarly, the temperature should be increased for heating mode, and the fan speed can be reduced. 

Examine The Internal System

If the problem continues, then you should check out the batteries then. Examine the system appropriately and remove the batteries. The batteries do stop working if they are being used for a longer time. Insert the same batteries again after rubbing them slightly, and if the thermostat does not operate, you have to change the batteries and insert the new ones. 

Time To Reset

Continuing the testing of the internal system, you can also check the filter inside. When the filter that passes out the air gets filled with excessive dust, it starts malfunctioning and generates faulty errors. Cleaning the filters and the processor responsible for throwing heat outside can help to sort the issue. 

If none of these steps work, you must reset the complete system. Check the main settings of the thermostat and follow the instructions from its manual book to reset the device. If you need help resetting independently, contact customer care and ask them for the procedure. 


Honeywell thermostats are popular because of their outstanding quality. They help control the air conditioner’s temperature and give satisfactory results. Like every other device, they can also cause trouble for you. Some thermostats keep blinking the cool on message, but now you don’t have to worry about it. The Honeywell Pro series thermostat cool on flashing can be fixed differently. Keep trying these steps, and your Honeywell thermostat will start functioning like before and release all your stress by giving out the natural cool-on effect.


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