Skip to Content

Why Is My Thermostat Blinking Heat On? (Honeywell, Carrier)

Generally, the thermostat is a device for controlling temperature to a certain point. Moreover, a thermostat can take action or give a signal when a certain point of temperature is reached. We use a thermostat in our houses to maintain a temperature that is not too cold or too hot. This device works automatically.

Sometimes, the thermostat doesn’t work well. For example, it might give a false signal or blink. So, you might be confused about why your thermostat is blinking heat on. Because generally, the thermostat represents a situation by “Heat on” or “Cool on” on the screen. But if these words are blinking, there might be a problem.

Why is my thermostat blinking heat on?

If your thermostat is blinking heat on, the device might be in a 5-minutes delay state. Moreover, the thermostat might blink when there is a power loss or low battery. Besides, when the temperature of your AC reaches the set point, the thermostat might blink “Cool on”.

However, several reasons might be responsible for why your thermostat is blinking heat on. A thermostat is supposed to show clean words like “Heat on” or “Cool on” on the screen. But whenever you notice the words are blinking, something is wrong with the device or outdoor unit.

Time delay:

Time delay is the most common reason why your thermostat is blinking heat on. Generally, Time delay is an indication of safety in your thermostat. Because, when the thermostat is 5 minutes delay that means a safety time has been stumbled to protect the compressor of the thermostat.

Sometimes, when the temperate reaches the set point of the thermostat, it can blink to show the state. But the time that has been lost during the process, will be delayed.

However, the time delay problem is for safety indications. The thermostat will return to its normal state when it stops blinking.

Power loss or low battery:

Another reason for blinking the thermostat is power loss. Generally, the disturbance in the power supply can create bad reading in the thermostat. Even the unusual blinking of the thermostat means power is not reaching the thermostat.

Moreover, a low battery can cause the thermostat to blink. When the battery is low and needs to be replaced, the thermostat will show blinking heat on. But when the battery has already been damaged, it will show a blank screen.

Otherwise, a low battery will show reading by blinking heat on. Whenever you see blinking, you should try to replace the battery of the thermostat.

Outdoor unit problem:

Whenever there is a problem with the outdoor unit, the thermostat might blink. Generally, a problem with the outdoor unit sends a signal to the thermostat. This signal causes the blinking of the thermostat.

But this doesn’t mean that the indoor unit is also affected. It is possible to create a problem in the outdoor unit and the indoor unit is running well. The thermostat blinking problem will not be solved until the problem of the outdoor unit is solved.

Why is my Honeywell thermostat blinking heat on?

Honeywell thermostat is a multifunctional thermostat that helps heating, cooling, ventilation, and AC system. This thermostat shows the temperature state readings on the screen. Sometimes, you might see the reading on the screen is blinking heat on.

Generally, the Honeywell thermostat blinks for protection purposes. A blinking heat on signal indicates that a safety timer’s tripping that will protect the compressor of your thermostat. Sometimes, it might indicate a low battery.

If the problem is with a safety timer or time delay, then the problem will be solved after resetting the thermostat. Moreover, replacing a battery will also help to return the thermostat to a normal state. Once these problems are solved, your Honeywell thermostat will stop blinking heat on.

Why are these thermostats blinking heat on?

Different types of thermostats are available. The main function of thermostats is the same. But their working ability and connections to temperature might be different. So, blinking heat on might also indicate different situations in different thermostats. Let’s see why some thermostats are blinking heat on.


Carrier thermostat is one of the modern thermostats. Generally, carrier thermostats control the temperature and air in your room. If you notice that your carrier thermostat is blinking heat on, this might indicate there is a problem in the outdoor unit. Moreover, power dropping can also cause blinking heat on in the thermostat.


Braeburn thermostat is a pretty easy and basic type digital thermostat. But you might see the thermostat is showing its reading by blinking heat on. Whenever you notice blinking in the Braeburn thermostat, it might be caused by the heat pump. Moreover, tripped circuit breakers might also cause the Braeburn thermostat to blink heat on.


Vivint thermostat is one of the smartest thermostats. Generally, the blinking heat on is created for the same reasons that make the traditional thermostat blink. For example, Vivint thermostat might blink heat on because of low battery or power dropping problem. Moreover, the outdoor unit problem might also be responsible.


Bryant thermostat is another smart thermostat that regulates heating, cooling, air-conditioning excellently. But if you see that your Bryant thermostat is blinking heat on, it might indicate several things.

For example, if there is an error code in the programming, it might show blinking. Sometimes, the power dropping or a tripped breaker might cause blinking of the reading on the screen.


Totaline is another digital thermostat that is also programmable. But sometimes, the time delay problem might give a blinking signal on the screen. Blinking might also be an indication of a low battery or power drop. So, you can reset the thermostat to solve the blinking problem.


Generally, the Lux thermostat shows a heat signal that indicates calling for heat. This thermostat is energy and cost-effective. But whenever there is a safety timer problem, the thermostat might blink heat on the signal. This signal also represents power loss, low battery, outdoor unit problems, etc.


Pro thermostat is another smart thermostat to control the heat and air of your room. But sometimes, the Pro thermostat might blink a signal. The reasons are the same for Pro thermostat blinking as the conventional thermostats. Resetting the thermostat can solve the blinking problem.

What does a blinking thermostat mean?

A blinking thermostat means several things. First of all, when you see your thermostat is blinking a signal, it indicates a time delay problem. This problem happens when the set temperature is reached and mismatch between the signal and temperature.

Moreover, when there is a problem in the outdoor unit, it might show a blinking signal. Sometimes, the indoor unit is running well but the outdoor unit has a problem. Besides, power loss or battery problems might give blinking signals.

Generally, replacing a battery will solve the battery problem. As a result, the blinking problem will also be solved. But you can also solve the issue by resetting the thermostat. You can set the thermostat if the thermostat is programmable. Otherwise, you will need professional help.

How to reset a thermostat that is blinking heat on?

Most of the thermostats are programmable. So, you can reset a thermostat to solve different problems. For example, if your thermostat has a blinking problem, you can solve it by resetting it. Let’s see how you can reset a thermostat that is blinking heat on.

Programmable Thermostat:

  • At first, switch off the thermostat from the electric connection or battery turn off the switch.
  • Remove the thermostat from the wall and open the battery door.
  • Then you have to remove the batteries.
  • Then you have to insert the batteries in the alternative direction to allow lining up negative sides to the positive terminal.
  • Keep the batteries in this position for five seconds.
  • Remove the batteries again and insert the batteries in the normal position.
  • Turn on the switch of the thermostat and check whether the thermostat is displaying or not.
  • If the display is showing results well, that means the thermostat has been reset.

Non-programmable Thermostat:

If the thermostat is non-programmable, you have to take the face-off and press the reset button for five seconds. You can also remove the batteries for five seconds. Then turn on the thermostat and check the display. If the screen is displaying all data, that means the thermostat has been set.

Final Thoughts

Your thermostat is blinking heat on signal because there might be a problem in the outdoor unit. Moreover, a time delay problem might give blinking signals. Besides, low battery or power loss problems might show blinking results. You can replace the battery or reset it to solve the problem.