my home made is wired from a normal light switch black to switch. then black in to high limit, black out to aquastat, black out from aquastat to junction box for fan and solenoid the blacks are all wire nutted together, the white that went into the light switch comes to this junction box and all whites are wire nutted together hear as well.
Turn the light switch off, no power to anything turn it on and power is in a string to everything but if something sticks or fails and water gets to 190, high limit cuts power to everything beyond it. high limit re-sets at 150 and off she goes again
Not sure how those fancy stoves do everything with a circuit board but the way i have mine has been dong fine for over ten years