Turned the system on, nothing turned on. Checked for power at the circuit board inside the furnace, there as no power. Started to remove the cover plate on the service switch at the furnace and the system turned on. Checked the wires on the switch, the power wire was not connected fully and came out of the terminal very easily. Secured the wires and tested. The switch did not turn the system on. The switch needs to be replaced. Replaced the service switch. Turned system on and checked the pressures and temps. The system is low on refrigerant. Added 6 oz R22. Turned the thermostat to heat and checked the operation.