CONNECTING THE ST620RF RECEIVER
NOTE: All electrical installation work should be carried out by a suitably qualified Electrician or other competent
person. If you are not sure how to install this digital thermostat consult either with a qualified electrician, heating
engineer or your boiler / heating system supplier for advice on how to continue.
The ST620RF Receiver should be mounted in a suitable location that is both accessible for the connection of mains
and control wiring, and allows good reception of the RF signal. The Receiver needs a 230V AC mains supply to
operate, and this should be fused appropriately (16A max.).
The Receiver should be mounted in a location where it will not come into contact with water, moisture or
condensation. There are few electrical connections required to the ST620RF, and these connections should be made
to the terminal block inside the Receiver. No Earth connection is required for the correct and safe operation of the
ST620RF, but a parking terminal is provided to connect an Earth wire if one is present.
These electrical connections are shown in the table below:
ST620RF INSTRUCTION MANUAL6
Terminal Function
COM Common Contact (volt free input)
NO Normally Open Contact (volt free output)
Earth Parking (No electrical connection)
L Incoming Mains - Live
N Incoming Mains - Neutral
