There are eight terminals on my thermostat. What color wire goes with each terminal?

What colors/letters do you have?

Wires: Orange, Green, Yellow, White, Red, Blue, Brown, Black

Thermostat: 8 terminals; O, G, Y, W, R, E, C, X1

We're assuming the OGYWR are, but we have no clue about the blue, brown, or black.

Thanks so much!

Check the connections at the unit.