The core of the boiler-control is a PID algorithm. There is a good explanation of the basic principles at Wikipedia.
We are constantly optimizing our PID implementation for agressiveness and correctness. The following recommendations are under constant review.
P-parameter
Current recommended values : between 20 and 25.
I-parameter
Current recommended value : 3.
D-parameter
Current recommended values: between 80 and 200.
Windowsize
For continuous mode: 1000ms ( 1 sec ), for interval mode: 5000ms ( 5 seconds ).
Window limit
Between 3000 and 4000.