How do I pair the RT520TX thermostat with the RXRT520 receiver?

Make sure the device is disconnected from power, then set the switches on the receiver to AUTO and ON, connect the receiver to the power supply, and wait for the red LED to light steadily. Then switch to the OFF position and back to ON quickly — a red flashing LED confirms pairing mode. The pairing process takes up to 10 minutes, and once successfully paired, the LED on the receiver will go solid red.