Salus ST621TX Instruction Manual page 12

Replacing the thermostat batteries will not affect the RF code setting. Pressing and holding
the SYNC button on the receiver will not clear the RF address code saved into the internal
memory, and switch the receiver into learning mode, as previously described.
TESTING THE RF TRANSMISSION
It is important to site both the receiver and thermostat in locations where the RF signal
cannot be interrupted. The receiving range between thermostat and receiver is 100 metres
in open air, however many factors can affect the RF transmission and shorten the operating
distance, e.g. shielding by thick walls, foil back plasterboard, metal objects such as filing
cabinets, general RF interference, and so on.
The operating range is generally around 30 metres, which is large enough for most
household applications, but it is advisable to test the RF transmission from the intended
thermostat location to the receiver location before fixing the thermostat to the wall.
The RF communication is one way, from the thermostat to the receiver – the receiver does
not send any signal back to the thermostat. The RF signal indicator only flashes once
when a signal is being transmitted.
The thermostat will transmit only when there is a need to control the heating system. Will
transmit once every twelve minutes.
12 ST621TX INSTRUCTION MANUAL