Salus iT500 - Pairing iT300 Sensor to Receiver

iT500 User Reference Manual
36
Pairing an iT300 with the iT500RX Receiver (optional)
The iT300 is purchased separately. It is only be used if your system supports two central heating zones.
Press to start sync. count down.
To pair the iT300 to the receiver, insert a paperclip or similar object into
the hole on the left hand side of the iT300 for 2 seconds.
A red light will ash in the top right hand corner of the iT300TX.
With the iT500 Thermostat in Normal mode press
and together for
two seconds. The following will be displayed.
The units will be paired once the count down has nished.