I have a nordyne heat pump model E2cho15ha. I had a technician hook up the board for the a/c over the summer but he never hooked up the heat. On the board there is a place for cooling and a place for heat, but when I put the orange wire on the heat my breaker pops and no heat. I have tried to obtain a diagram but no luck. Can you help me?

It may help if you give the board part number your trying to install. If the breaker is tripping as soon as you turn it on--- you probably took out the board again.

Wire colors and terminal letter designations should match up at the thermostat, indoor unit, and outdoor unit. "O" circuit may or may not be directly connected to the indoor unit.