On 10 Dec, 12:35, "Doctor Drivel" wrote

How did you fine tune a CH system with it?

I have a separate thermostat in the master bedroom to maintain a
minimum night-time temperature. I used the data logger to establish
the normal temperature drop off rate and the night-time warm up rate
to optimise the night-time boiler burn time. Also used it to
establish normal boiler cycle time (I once had a boiler problem with
short-cycling), and to optimise the radiator ouputs for each of the
rooms.

CRB