Relays are devices making or breaking electric circuits by their output section driven by an operational signal, which is triggered by electric input signal controlled by switching devices.
The main operation of the relay board comes in places where only a low-power signal from a Raspberry PI can be used to control a circuit of your heating system.
- Connect GND pin of the Relay with GND pin of the Raspberry PI
- Connect VCC pin of the Relay with 5V pin of the Raspberry PI
- Connect IN1-IN4 pin with GPIO pins.
MAINS USE should NEVER be attempted by anyone unfamiliar, not competent and not qualified. The whole board including Pi should be enclosed in an isolated enclosure. We accept no responsibility for misuse at any voltage, including mains. MAINS CAN KILL!