I have been using a Non-proprietary (24 VAC) multi-speed fan system to make my home a comfortable one for my family. I could not use Ecobee Smart Thermostat with that due to incompatibility.
I found out that the latest Ecobee firmware version 4.6.3 has enabled compatibility with several more systems.
The latest firmware update has enabled the compatibility with several more low-voltage multi-speed fan systems such as FCU (Fan Coil Unit) and Non-proprietary (24 VAC) multi-speed fan systems.
It was the first time I chose an Ecobee thermostat, and I decided to configure everything all by myself. I thought it would be an excellent opportunity for you too.
What single-transformer multi-speed systems can I use with the ecobee?
I found out that only the below HVAC systems support the ecobee.
- 2-Pipe or 4-Pipe Fan Coil Units (FCUs)
Note: I inquired about ecobee with the Aux Heat compatibility. They mentioned I could go with or without Aux Heat.
- Non-proprietary (24 VAC) multi-speed fan systems with (G1, G2, and G3)
- Multi-speed PTAC systems
You can’t use the Dual-transformer systems as they don’t support the variable speed fan feature.
What Ecobee models are compatible with variable speed features?
I found only a few models support the variable fan speed feature.
- Ecobee3 Lite
- Smart Thermostat with voice control
- ecobee4
- Smart Thermostat Premium
- Smart Thermostat Enhanced
What systems are not compatible with the ecobee variable speed feature?
The following system won to support the ecobee variable speed feature.
- Dual-transformer systems
- Note: Since thermostats require Rc and Rh wires and the ecobee Power Extender Kit, which are not compatible.
- Fan-coil units that need to be fixed with the G1, G2, and G3
- Every AC system that comes with a multi-speed fan
If you can’t figure out whether your home supports the ecobee thermostat or not, the fowling link will help you to do that.
What Ecobee thermostat models are not compatible with variable speed features?
I discovered that ecobee3 thermostats and previous versions don’t support the variable fan speed feature. It means SMART, Smart Si, EMS, and EMS Si are incompatible with the variable or multi-fan speed feature.
What firmware versions support the variable fan speed feature?
I discovered that the firmware version of the ecobee thermostat must be updated to the latest version to ensure an effective outcome. The problem is “I’m a pro” option not being available in the setup process.
Although you have an Ecobee thermostat device in the compatible list, you must make sure it has been updated to the latest version.
How to know the ecobee firmware thermostat version?
You may follow the below steps to know the firmware thermostat version.
1. Go to the ecobee thermostat interface.
2. Navigate into the Main Menu section.
3. Then select the About option.
4. In the about section, you can find the ecobee version.
How to update the ecobee firmware thermostat version?
I prepared a table including the ecobee thermostats with the latest firmware versions for an effective variable speed fan functionality.
| Device | Latest Firmware Version |
| Smart Thermostat Premium | 4.7.34.212 |
| Smart Thermostat Enhanced | 4.7.34.214 |
| Smart Thermostat with Voice Control | 4.7.5.352 |
| ecobee4 | 4.7.5.246 |
| ecobee3 lite | 4.7.5.244 |
You don’t have to bother updating the ecobee device’s firmware version as they update automatically. But, I discovered some users whose thermostats had not been updated. If you have a wrong reading between the ecobee devices and the table, we recommend you to do the below things.
- Check the Wife connection of your ecobee thermostat device
- Check if your Wii has been connected to the internet
- Wait for a couple of days until the latest updates reach your device
Note: I discovered that auto-updating is completed within 10 minutes. But it may take a few days to reach them on your ecobee device.
- Contact Ecobee customer care
How to repurpose the ecobee for a variable fan speed system?
As a new ecobee user, I purposed everything from the beginning. But, even as an existing ecobee user, you need to repurpose specific wiring terminals. I have tabled out the repurpose points you need to follow.
Note: You don’t have G2/G3/S1/S2 terminals. Therefore, the repurposing is addressed to overcome that barrier.
| Existing Terminal | Repurpose unit | Fan / Wire |
| The Y2 terminal | G2 | medium fan speed |
| W2 terminal / PEK+ on the Smart Thermostat Enhanced | G3 | High speed fan |
| The Rh terminal | S1 | pipe sensor wire |
| The PEK terminal | S2 | pipe sensor wire |
Note: You can place Only one wire in each terminal at a time.
Also, you cant use a Power Extender Kit for the 2-pipe FCU system, as it is necessary to utilize the PEK terminal for the sensor.
When conducting the wiring of the ecobee for a multi-speed fan system
- The low-speed fan wire (usually known as G, Gl, or G1) must go to G on the ecobee
- The medium-speed fan wire (usually known as G2 or Gm) must go to Y2 on the ecobee
- The high-speed fan wire (usually known as G3 or Gh) must go to W2 on the ecobee
- Note: If the Smart Thermostat has been enhanced, it must go to PEK+
When conducting the wiring of 2-pipe FCU systems that utilize a pipe sensor/ changeover sensor / AquaStat:
- The S1 wire must go to the Rh terminal on the ecobee
- The S2 wire must go to the PEK terminal on the ecobee
Note: I read the warranty for the ecobee thermostats, and it mentioned that the warranty would not be applicable when the user conducted Incorrect wiring or configuration.
If you find these steps a bit confusing, you must follow the below link to find a professional installer in the area.
How to configure the ecobee thermostat for variable fan speed?
I found these simple steps to configure the ecobee thermostat for variable fan speed.
Power up the ecobee thermostats
- Tap, let’s get started
- Chose I’m a pro
Note: I discovered that the “I’m pro” option would not be available if your device is not up to date. Therefore, go through the update process and then proceed to the configuration.
- Read the warning message and choose Accept
- Choose Yes, only Rc is connected
- Tap Next
Choosing The Fan Speed
At this point, you must choose the fan speed. That should be done according to the G wires and the pipe sensor wires.
- Choose a Single or Variable Speed Fan if you have only one G wire
- Choose a Multi-speed fan if you have several G wires
- Choose a Multi-speed fan and pipe sensor if you have several G wires and pipe sensor wires
Setting Up Single Or Variable-Speed Fan
- Read the wiring configuration and choose yes if it is correct
- If the configuration is incorrect, choose No and then choose Modify to change them manually
- Complete the on-screen configuration to complete the process
Why can’t you configure the ecobee thermostats for variable fan speed?
I went through several user experiences before setting up the ecobee thermostat at my home. I realized that the only error a user may get is not to have “I’m a pro” in the setup.
If the problem exists even after the firmware update, you must reset the thermostat device.
- Go to the thermostat screen
- Choose Main Menu in the bottom left
- Tap Settings
- Tap Reset
- Choose Reset All
- Confirm
- Try to set up the ecobee variable speed fan again
Conclusion
I hope you must have been able to set up your ecobee variable speed fan. If there are still issues, please contact the official ecobee assistance.