If your Ecobee thermostat is blowing cold air instead of hot or blowing hot air instead of cold, you could have incorrect thermostat wiring or your reverse valve could be stuck in one position (if you have a heat pump). To fix this problem check thermostat wiring and settings
Typically, when you have a heat pump you should have an O/B terminal connected and ensure that you switch between cooling and heating on your thermostatic. Let’s take a look at more AC condenser unit not working (for heat pumps)
common causes for an Ecobee whose heating and cooling is reversed.
Causes of Ecobee Thermostats Blowing Cold Air On Heat
Incorrect thermostat setting
One common cause of an Ecobee thermostat blowing cold air is that the thermostat may be set to the wrong mode or temperature. For example, if the thermostat is set to “cool” instead of “heat,” or if the temperature is set too low, it can cause the heating system to blow cold air instead of warm.
Wrong thermostat wiring
Incorrect wiring can cause an Ecobee thermostat to malfunction and blow cold air instead of heat. This can occur if the O/B terminal, a terminal for the reversing valve, is not connected or whose wiring is loose
AC condenser unit not working
For heat pump systems, if the AC condenser unit is not working properly, it can cause the Ecobee thermostat to blow cold air instead of heat. For heat pumps, the condenser absorbs heat from the outdoor air. So when this unit is not working or when it is not powered up, your indoor air handler could be blowing cold air only.
Read also: Ecobee not cooling to set temperature
Stuck reversing valve
In heat pump systems, a stuck reversing valve can cause the Ecobee thermostat to blow cold air instead of heat.
The reversing valve is responsible for changing the direction of the refrigerant flow, which determines whether the system provides heating or cooling.
If the reversing valve is stuck in the cooling position, it can cause the system to blow cold air instead of warm.
How to Identify the Cause of the Problem
Steps to take to troubleshoot the issue
Check the thermostat settings: Check that the thermostat is set to the correct mode (heat instead of cool), and that the temperature setting is appropriate for the desired heating level.
Check the AC condenser unit (for heat pump systems): Inspect the unit for any visible signs of damage, and check that it is receiving power. You may also want to check that the compressor is working properly and the condenser fan is running.
Check the reversing valve: You can test the reversing valve by engaging the heating mode and listening for a clicking sound, which indicates that the valve is changing the flow of refrigerant. If you do not hear a clicking sound, the reversing valve may be stuck.
Read also: Nest thermostat blowing cold air on heat
How to Fix an Ecobee Thermostat Blowing Cold Air
Correcting the thermostat setting
If the thermostat is set to the wrong mode or temperature, adjust it to the correct setting. For example, switch the thermostat from “cool” to “heat,” and adjust the temperature setting to a desired level for heating.
Fixing the wiring
Inspect thermostat wiring. Find out what type of heating system and check if the wiring corresponds. If you are using a heat pump with aux heat, you would have a wire connected to the O/B terminal and the AUX or W1 terminals.