I started a little project to control my Bosch central heating boiler from Homeseer using my RFXIO. I have a Bosch HRC-35 Top, which has a built-in controller (called Heatronic) which I use to heat my house based on the outside temperature (weersafhankelijke regeling in dutch). The controller itself can be programmed using a week program.
This works fine, but when I am not at home at a certain day, I have to go upstairs to change this on the boiler itself, which is not pratical. So I would like to control the central heating from my domotica system (HomeSeer).
The boiler itself has no simple input line (except for a on/off or OpenTherm thermostat). But I found that Bosch has a remote control for this boiler, the Bosch TW2.
This remote control has a wheel to manually change the program of the Heatronic: night program, day program, automatic program or frost protection. My idea is to replace this wheel, and replace it by a few relays such that I am able to control it using my RFXIO. The nice thing is that the actually controlling still takes place within the boiler, and that I am only changing the program.
The wheel is actually a switch with 1 input and 4 output. Depending on the state of the switch, the input is connected to 1 of the outputs. My plan is to use 2 or 3 relays to simulate this switch, controlled by 2 output ports of my RFXIO.
But as I'm not really an expert in electronics, I am wondering whether there are "better" solutions than using the relays which I've in mind. Maybe there exists a nice standard component to achieve this. Suggestions are welcome.
