Exactly what I saw earlier. So no OT for me until that is fixed.
Ah well, I think on/off works just as well, taking into account the boiler then also modulates its heat output to the set (55C) temperature. I do not know about the gas use but at least the electricity use is much lower, as one big difference I also noticed was that, under OT, the boiler pump was hardly switched off at all. More or less during the entire day it ran, albeit slow, most of the time pumping 20-25C water around. Now with on off the boiler heats and pumps water around until the heat request disappears, then pumps for another couple of minutes and then switches off.