Control gas boiler with relay by connecting it to room thermostat connection on gas boiler without passing any current to gas boiler or at least this is how i did it and not to worry about buildup pressure inside heating pipes as gas boiler controller takes care of that itself.

You can control High Voltage electronic devices using relays modules that are readily available in the market. I am using the HL-52S 2 channel relay module, which has 2 relays. The high voltage side output connector has 3 pins, the middle one is the common pin and as we can see from the markings on

Boiler Room Thermostat Connection

Boiler Room Thermostat Connection

e of the two other pins is for normally open connection and the other one for normally closed connection. The reason i m using two channel relay as i can not find any single channel relay with optocoupler ic.

“DO NOT MAKE ANY CHANGES TO YOUR HEATING SYSTEM UNTIL UNLESS YOU KNOW WHAT YOU ARE DOING, contents provided here are for information and education purpose only, I take no responsibility for any loss or damage to you or your property.”

 

MySensors Arduino Sketch to Control Gas Boiler Relay