[kkl]

My geothermal heat pump requires a thermostat that provides both an O and a B signal. My Braeburn thermostat provides this, but I’d like to get something that is TCP/IP (Ethernet/WiFi) or Z-wave controllable. However, after extensive searching I’ve found that most high tech thermostats provide either an O or B signal, but not both. I’m interested in the Ecobee. My current wires are W1, W2, Y1, C, R, O, B, G. Rather than just controlling a reversing valve, the O & B signals tell the GSHP control module which mode to be in. There’s one Tekmar controller that turns on in heating mode, a second one in cooling mode, and they’re both off when the thermostat is off.

Since the Ecobee, as an example, provides only O or B, would it be possible to use a relay or something similar to provide the other signal? If set to provide O (cooling):