If your equipment is 2-stage, first make sure your DIP switches are set correctly to allow second stage operation. In order to bring on second stage faster than the efficient fuzzy-logic algorithm (about 15-20min after first stage, if needed):
1) set the heating or cooling setpoint at the room temperature and let the display return to normal operation.
2) move the heat or cool setpoint up or down three degrees. After normal protection time-outs have been satisfied (2 or 4 minutes depending on your configuration), the thermostat will start first stage.
3) Once first stage is running, adjust the setpoint three more degrees in the same direction. Second stage will start.
This method bypasses thermostatic control algorithm for this single heating / cooling cycle.