www.hvactechgroup.com - forums

HVAC Forums => HVAC Help => Topic started by: pilotcass on November 25, 2025, 10:54:38 PM

Title: Ecobee Premium + HRV-150 WOL — How to interface 3-wire OBCS control with Ecobee?
Post by: pilotcass on November 25, 2025, 10:54:38 PM
I have an older Lennox Healthy Climate HRV-150 WOL ventilation unit that uses a 3-wire wall controller:

Red = +12V
Black = Common
Orange = OBCS

I am trying to install an Ecobee Premium thermostat and would like it to control the HRV with it, but the Ecobee only provides a (ACC+, ACC–).

Is there any way to connect Ecobee directly to this HRV?
Any guidance, wiring diagrams, or confirmed setups would be appreciated.

HRV Wiring Diagram: https://imgshare.cc/uanp4lg2
HRV Wall Controller: https://imgshare.cc/gjwlldu6

Thanks!