Ecobee wiring issue

[deep]

I have to change the thermostat to ecobee thermostat. I am attaching pictures. I tried installing it, but cool mode is not working.

Can anyone please help me, how to wire this furnace? Is Ecobee compatible or not?

[Admin]

What kind of heating system is that?  It looks like the old thermostat was a communicating type, so you need to re-wire the low voltage and use R, C, W1, G, Y1.  If you only have 4 wires you need to use the PEK adapter.