410. Pairing your RXBC605iT500BM Installer Manual 271Ensure the switch on the RF integral boilermodule is in the AUTOGently press and hold the SYNC button with a bluntobject. After 3 seconds the Boiler Control LED willflash once every second to indicate it is ready to pairand ready to receive a signal from the thermostat*.MANUAL AUTO2 SYNC Button+3