Ecobee Smart Thermostat + HRV Ventilation System Installation Help!

[mythx1]

Hey everyone! I found this forum when I was searching for some help.

We've just moved into a new house and I am looking to replace the existing non-smart thermostat to a smart one (ecobee premium). There is also an HRV controller (Healthy Climate 99-BRHRV Control Module) right beside the old thermostat. I've been reading that it can be controlled by the ecobee as well. How do I go about doing this?

I am attaching the pictures of everything on this post. I am not very technical when it comes to these things but I want to give this a shot before calling someone to do it for me. Would really appreciate some help wiring it all together. I am able to drill holes to install the backplate for the ecobee.

[Admin]

In your case you would have to disconnect the three wires off the HRV controller and bring them over with the thermostat wires.  Hopefully there's not a stud behind the drywall, between the thermostat and HRV controller otherwise you might have to cut or notch a little drywall.  You will likely have to patch and paint after replacing both controls with the Ecobee anyway.  The red and green wires will become Ecobee ACC and the blue wire will become Ecobee C.

You can disconnect all the wires connected to the HRV unless you have bathroom timers then you need to leave them connected.

Your existing thermostat does not have a C wire but the Ecobee will require it.  You will have to remove the Y wire from the HRV and connect it to the C terminal in the furnace.  Keep in mind the Ecobee will control the furnace fan so the interlock wiring between the HRV and furnace can be disconnected and re-used.

The only thing that should be connected to the G terminal in the furnace is the G wire from the Ecobee.  If there was interlock wiring installed between the HRV and furnace you will have to change how it is connected.  It looks like there is interlock wiring and that blue marrette with the blue and green wires is what you need to disconnect.  I believe the green wire is the G wire from the thermostat and should now be connected directly to the G terminal on the furnace.  So remove the existing G wire from the furnace G terminal and connect the green wire you removed from the marette, to the furnace G terminal.  Take the blue wire you removed from the marrette and connect it to the C terminal in the furnace.  Note, there should already be a wire connected to furnace C for the AC.  Now use the marrette to connect the blue wires you disconnected from the HRV Y and NC terminals, at the HRV.  This is now your C wire between furnace and thermostat.  You also want to disconnect the red wire from the furnace R terminal that connected to the HRV NO terminal.  This should leave you with two unused wires at the furnace and HRV.

The HRV controller R and G wires would connect to the Ecobee ACC terminals.  Basically you would remove all the wires from the HRV (except for bath timers) and install a jumper between ON and RED.  Then the Ecobee ACC wires would connect to ON and HI.  (The 2 wires removed from HRV R and G). See pic.

When you set up the Ecobee you will have to set up the ventilation settings for the HRV.