Node-Red and DAC

I would like to control my water heater element with a power controller. The controller requires 0-5V DC to control the element output.

I was hoping to use a Click analog output module (ADAC Click) atop my raspberry Pi 3 but am struggling to work out how to control the output module.

Information provided is here:

I am struggling to communicate with the ADAC click using the i2c input and output nodes.
I get the the address back when I use the i2c scan node.

The issue is interpreting the information relating to the AD5593R


It looks to me like you would need to write your own low level library just to communicate with this thing.
I have had good success controlling high amperage loads with this IOT relay plug:
Just a simple high and low will turn it on and off. For simple projects, I just use a normal relay board but for a high amp load like a heater, I want to be sure my hacked project does not burn down my house.

Google suggests that there is little support for this for the Pi, unless I missed it. You might be better to find a DAC that is well supported and use that.