Here are some reasons why your ecobee might be restarting when the heat turns on
If the thermostat is not set correctly, it can cause the furnace to turn on and off repeatedly.For example, if the thermostat is set to a higher temperature than the actual temperature in the house, the furnace will turn on to heat the house. However, once the house reaches the desired temperature, the thermostat will turn off the furnace. The furnace will then turn back on when the temperature in the house drops below the set point. This cycle can repeat itself several times before the house reaches the desired temperature.
There could be a problem with the furnace itself that is causing it to restart. For example, the furnace may be overheating, which can cause it to shut down as a safety precaution. The furnace may also have a faulty igniter, which can prevent it from starting properly. If the furnace has a problem, it is important to have it inspected by a qualified technician.
There may be a problem with the power supply to the furnace that is causing it to restart. For example, there may be a loose wire or a blown fuse. If there is a problem with the power supply, it is important to have it fixed by a qualified electrician.
There may be a problem with the software that is running on the ecobee. This could be due to a bug in the software or a conflict with another program that is running on the system. If there is a problem with the software, it is important to update the software to the latest version.
If your ecobee is restarting repeatedly, it is important to troubleshoot the problem to find the cause. Once the cause is found, you can take steps to fix the problem and prevent it from happening again.