Honeywell Thermostat Flashing Heat On? Here’s How to Fix It

Have you ever encountered the annoying situation where your Honeywell thermostat is flashing heat on and not heating up your home? If so, you are not alone. Many homeowners have faced this problem and wondered what it means and how to fix it.

In this article, we will explain the possible reasons for a Honeywell thermostat flashing heat on and how to troubleshoot and resolve them. We will also provide some tips on how to prevent this issue from happening again and answer some frequently asked questions. By the end of this article, you will have a better understanding of your Honeywell thermostat and how to keep it working properly.

Also Read – Honeywell Thermostat Not Communicating with Boiler – Troubleshoot Guide

Possible Reasons for a Honeywell Thermostat Blinking Heat On

There are several possible causes for a Honeywell thermostat blinking heat on message. Some of them are easy to fix, while others may require professional assistance. Here are some of the most common ones:

• Time Off Delay
• Power Loss to the Condenser Unit or the Air Handler
• Blown Fuses
• Malfunctioning Control Board
• Open High Limit Switch
• Tripped Float Switch

How to Fix the Heat On Flashing Message on Honeywell Thermostat?

If you have identified the cause of the problem and applied the appropriate solution, you should be able to fix the heat on flashing message on your Honeywell thermostat and restore the normal operation of your system. However, if you are still unsure of the cause of the problem or the solution, you can try some general troubleshooting steps that may help you resolve the issue. Here are some of them:

Also Read – How to Set Honeywell Thermostat Temperature? (Heat and Cool)

Time Off Delay

One of the simplest and most common reasons for a Honeywell thermostat flashing heat on is the time off delay feature. This feature is designed to protect your HVAC system from short cycling, which is when the system turns on and off too frequently and causes damage to the components.

The time off delay feature prevents the system from turning on again until a certain amount of time has passed after the previous cycle. This allows the system to cool down and stabilize before starting a new cycle. The time off delay can range from a few seconds to several minutes, depending on the model and settings of your thermostat.

When the time off delay is active, your thermostat will flash heat on and not turn on the system until the delay is over. This is normal and not a sign of a problem. You just need to wait patiently for the delay to complete and then your system will resume normal operation.

You can expect the time off delay to occur in some scenarios, such as after a power outage, a sudden temperature change, or a manual adjustment of the thermostat settings. You can also adjust the time off delay settings on your thermostat if you want to shorten or lengthen the delay time.

Also Read – Honeywell Thermostat Waiting for Equipment Message [Explained and Solved]

Power Loss to the Condenser Unit or the Air Handler

Another possible reason for a Honeywell thermostat flashing heat on is a power loss to the outdoor unit (the condenser unit) or the indoor unit (the air handler) of your heating system. This can happen due to various reasons, such as a tripped circuit breaker, a loose wire, a faulty switch, or a damaged component.

When the power is lost to either the condenser unit or the air handler, the thermostat will not be able to communicate with the system and will flash heat on and not turn on the system. This can also cause the system to malfunction and display error codes on the thermostat screen.

To fix this problem, you need to check the power supply to both the outdoor and indoor units and make sure they are receiving adequate voltage. You can do this by following these steps:

• Locate the circuit breaker panel in your home and find the breakers that control the power to the condenser unit and the air handler. Make sure they are in the ON position and not tripped. If they are tripped, reset them by flipping them off and on again.
• Locate the disconnect switches near the condenser unit and the air handler. These are usually metal boxes with a handle or a lever that can be pulled out or pushed in to cut off or restore the power to the units. Make sure they are in the ON position and not disconnected. If they are disconnected, reconnect them by pushing them in or pulling them out.
• Check the wiring connections between the thermostat, the condenser unit, and the air handler. Make sure they are secure and not loose or damaged. If you see any signs of wear or tear, such as frayed wires, exposed wires, or burnt wires, do not touch them and call a professional for repair.

If you have checked the power supply and the wiring and everything seems fine, but the problem persists, you may have a faulty component in the system, such as a transformer, a capacitor, a relay, or a control board. In this case, you will need to call a professional to diagnose and replace the faulty component.

Also Read – Turn off Recovery Mode on Honeywell Thermostat – How to Override Explained

Blown Fuses

Another possible cause for a Honeywell thermostat flashing heat on is a blown fuse in the system. A fuse is a small device that protects the system from overcurrent or short circuit by breaking the circuit when the current exceeds a certain limit. A fuse can blow due to various reasons, such as a power surge, a faulty component, or a wiring issue.

When a fuse blows, the system will lose power and the thermostat will flash heat on and not turn on the system. This can also cause the system to malfunction and display error codes on the thermostat screen.

To fix this problem, you need to locate and inspect the fuses in the system and replace them if they are blown. You can do this by following these steps:

• Locate the fuses on the control board or the transformer of the system. The control board is usually located inside the air handler, while the transformer is usually located near the condenser unit. The fuses are usually small cylindrical or rectangular devices with metal caps on both ends. They may have a label or a color code indicating their rating and type.
• Inspect the fuses for any signs of damage or burn marks. You can also use a multimeter to test the continuity of the fuses. A good fuse will have a low resistance (close to zero), while a blown fuse will have a high resistance (infinite or open).
• Replace the blown fuses with new ones that have the same rating and type as the original ones. Do not use a fuse with a higher or lower rating or a different type, as this can cause more damage to the system or create a fire hazard.
• Check the wiring and the components in the system for any signs of damage or short circuit that may have caused the fuse to blow. If you see any signs of wear or tear, such as frayed wires, exposed wires, or burnt wires, do not touch them and call a professional for repair.

If you have replaced the blown fuses and the problem persists, you may have a faulty component in the system, such as a transformer, a capacitor, a relay, or a control board. In this case, you will need to call a professional to diagnose and replace the faulty component.

Malfunctioning Control Board

Another possible reason for a Honeywell thermostat flashing heat on is a malfunctioning control board in the system. The control board is the brain of the system that controls and monitors the operation of the system and communicates with the thermostat. The control board can malfunction due to various reasons, such as a power surge, a faulty component, a wiring issue, or a software glitch.

When the control board malfunctions, the system will not work properly and the thermostat will flash heat on and not respond to your commands. This can also cause the system to malfunction and display error codes on the thermostat screen.

To fix this problem, you need to diagnose and test the control board for any signs of damage or error codes. You can do this by following these steps:

• Locate the control board inside the air handler or near the condenser unit. The control board is usually a rectangular or square device with several wires and connectors attached to it. It may have a label or a sticker indicating the model and serial number of the board.
• Inspect the control board for any signs of damage or burn marks. You can also use a multimeter to test the voltage and the resistance of the board. A good board will have a normal voltage (around 24 volts) and a low resistance (close to zero), while a bad board will have an abnormal voltage (too high or too low) or a high resistance (infinite or open).
• Check the error codes on the control board or the thermostat screen. The error codes are usually alphanumeric codes that indicate the type and the source of the problem. You can refer to the user manual or the manufacturer’s website for the meaning and the solution of the error codes.
• Reset the control board by turning off the power to the system and waiting for a few minutes. Then turn on the power again and see if the problem is resolved. Sometimes, a simple reset can clear the error codes and restore the normal operation of the board.
• Replace the control board with a new one that is compatible with your system and your thermostat. Do not use a board that is not designed for your system or your thermostat, as this can cause more damage to the system or create a fire hazard. You can order a new board from the manufacturer or a reputable online store.

If you have diagnosed and tested the control board and the problem persists, you may have a faulty component in the system, such as a transformer, a capacitor, a relay, or a thermostat. In this case, you will need to call a professional to diagnose and replace the faulty component.

Open High Limit Switch

Another possible reason for a Honeywell thermostat flashing heat on is an open high limit switch in the furnace. The high limit switch is a safety device that protects the furnace from overheating by shutting off the gas valve when the temperature inside the furnace exceeds a certain limit. The high limit switch can open due to various reasons, such as a dirty air filter, a blocked airflow, or a faulty blower motor.

When the high limit switch opens, the furnace will stop heating and the thermostat will flash heat on and not heat up your home. This can also cause the furnace to malfunction and display error codes on the thermostat screen.

To fix this problem, you need to locate and reset the high limit switch on the furnace and address the cause of the overheating. You can do this by following these steps:

• Locate the high limit switch on the furnace. The high limit switch is usually a small rectangular or round device with two wires attached to it. It may have a label or a sticker indicating the temperature limit and the model number of the switch. It is usually located near the burner or the heat exchanger of the furnace.
• Reset the high limit switch by pressing the small button or lever on the switch. You should hear a click sound when the switch is reset. If the switch does not reset, it may be faulty and need to be replaced.
• Check the air filter and the airflow in the system. A dirty air filter or a blocked airflow can cause the furnace to overheat and trip the high limit switch. You should clean or replace the air filter regularly and make sure there are no obstructions in the vents, ducts, or registers of the system.
• Check the blower motor and the fan. A faulty blower motor or a damaged fan can cause the furnace to overheat and trip the high limit switch. You should inspect the blower motor and the fan for any signs of wear or tear, such as noise, vibration, or dust. You should also lubricate the motor and the fan if needed and make sure they are spinning properly.

If you have reset the high limit switch and addressed the cause of the overheating, but the problem persists, you may have a faulty high limit switch or a faulty thermostat. In this case, you will need to call a professional to diagnose and replace the faulty component.

Tripped Float Switch

Another possible reason for a Honeywell thermostat flashing heat on is a tripped float switch in the condensate drain pan. The condensate drain pan is a device that collects the water that is produced by the heating and cooling process of the system. The float switch is a device that detects the water level in the drain pan and shuts off the system when the water level is too high. The float switch can trip due to various reasons, such as a clogged drain line, a cracked drain pan, or a faulty float switch.

When the float switch trips, the system will stop working and the thermostat will flash heat on and not turn on the system. This can also cause the system to malfunction and display error codes on the thermostat screen.

To fix this problem, you need to locate and drain the condensate drain pan and the float switch and address the cause of the water accumulation. You can do this by following these steps:

• Locate the condensate drain pan and the float switch in the system. The condensate drain pan is usually a metal or plastic tray that is located under or near the air handler. The float switch is usually a small device that is attached to the drain pan or the drain line. It may have a label or a sticker indicating the model and serial number of the switch.
• Drain the condensate drain pan and the float switch by removing the plug or the cap on the drain line and letting the water flow out. You may need a bucket or a hose to collect the water. Be careful not to spill the water or damage the drain line.
• Reset the float switch by lifting it up and down a few times. You should hear a click sound when the switch is reset. If the switch does not reset, it may be faulty and need to be replaced.
• Check the drain line and the drain pan for any signs of clogging or cracking. A clogged drain line or a cracked drain pan can cause the water to back up and trip the float switch. You should clear the drain line with a wet/dry vacuum or a drain snake and repair or replace the drain pan if needed.

If you have drained the condensate drain pan and the float switch and addressed the cause of the water accumulation, but the problem persists, you may have a faulty float switch or a faulty thermostat. In this case, you will need to call a professional to diagnose and replace the faulty component.

Power Cycling

One of the simplest and most effective troubleshooting steps is power cycling the system. Power cycling is the process of turning off and on the power to the system and the thermostat. This can help reset the system and clear any error codes or glitches that may be causing the problem.

To power cycle the system and the thermostat, you can follow these steps:

• Turn off the power to the system and the thermostat by flipping the circuit breaker or the disconnect switch to the OFF position.
• Wait for at least 10 minutes to allow the system and the thermostat to cool down and reset.
• Turn on the power to the system and the thermostat by flipping the circuit breaker or the disconnect switch to the ON position.
• Check the thermostat and the system and see if they work properly. Make sure the thermostat is set to the correct mode and temperature and the system is not flashing heat on anymore.

If power cycling the system and the thermostat does not resolve the problem, you may need to try other troubleshooting steps or call a professional for assistance.

Also Read – Honeywell Thermostat Unable to Obtain IP Address: How to Fix It

Conclusion

We hope this article has helped you understand the possible reasons for a Honeywell thermostat flashing heat on and how to fix them. By following the troubleshooting steps and the solutions we have provided, you should be able to resolve the issue and enjoy a comfortable and cozy home.

However, if you are still having trouble with your Honeywell thermostat or your heating system, you may need to contact the manufacturer or a qualified technician for further assistance. They can help you diagnose and repair the problem and ensure the safety and efficiency of your system.

If you have any questions or feedback about this article, please feel free to leave a comment below or contact us through our website. We would love to hear from you and help you with your HVAC needs.

Thank you for reading and have a great day! 😊

Check Out – How to Fix a Honeywell Thermostat Fan Won’t Turn Off