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Ecobee Smart Thersmostat with ERV (Wiring Options)

I currently have an ERV wired to my Ecobee Smart Thermostat. I’m not really happy because the only option I have is to operate the ventilator at max speed for 20 Minutes. Ecobee was supposed to add more features to control ventilators but it never happened. I was wondering if there are other wiring options for a setup like mine.

Right now, the furnace fan is running 40mins per hour. Would it be possible to wire the ERV to the Ecobee Smart Thermostat so that when there is a call to start the furnace fan to also start the ERV ? This way, the ERV would work for (a minimum) of 40mins per hour.


  • dborndborn Montreal, CanadaMember

    Depends what you want to use it for. I don't think ERVs are useful for lowering the humidity (compared to an HRV) so in that case, connecting it as a dehumidifier is out of the question. Your ERV doesn't have an automatic (but separate from the tstat) way of having it turn on/off based on a timer?

    You could use a small 24vac relay connected to the fan ouput (G) of the Smart so that it would open or close the contact when the fan is activated and this would trigger the ERV to follow along..?

  • Hi

    Thanks for the help.

    What I want is to be able to run the ERV for about 30-40mins per hour. Currently, I don’t have a wall control since the wall control that came with the unit is simply a humidistat and I don’t want to control the ERV based on the humidity.

    I have searched for the options that could work and I have stumbled upon a HRV/ERV controller made by RenewAire (RenewAire PTL Control Manual). This control is letting you select how many minutes per hour you want to run the unit.

    I was wondering how could I connect this unit to the Ecobee EIM so that:

    1. Using the RenewAire control, I could define the number of minutes per hour to run the ERV. The control would turn on the ERV and the furnace fan; and

    2. Using the Ecobee thermostat, I could still start the ERV at the maximum speed for 20 mins (only option available via the Ecobee thermostat)

    Would the wiring diagram below work (note that HRV on the diagram should be ERV) ?

    Ecobee Smart Thermostat Manual (Installation)

    RenewAire PTL Control Manual

  • dborndborn Montreal, CanadaMember
    edited January 2015

    What I would do is use the RenewAire controller for your ERV and your hurnace fan in parallel and also use the Smart for also both these devices. Since both ERV and furnace fans are controlled by 24vac signals, I would keep it simple (and reliable) and just go with one or two SPDT/DPDT 24vac relays to do what you want to do.

    Let me know if you need help with figuring out the wiring schematic for this.

  • Thanks dborn,

    I have looking on the RenewAire website and noticed that they have the same control but made to support furnace interlock.

    See Manual: http://www.renewaire.com/images/stories/products/fm/fm_manual.pdf

    Would this be easier for my setup ?

  • dborndborn Montreal, CanadaMember

    Without being an expert on the subject, it certainly looks like this is what you're looking for!

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