hello
My settings of the s4 are
boiler temp 83
return temp 63
flue gas working temp set to 190C
lambda is set to 9%
Most of the time my ventilator works around 50%. At summer it takes 7 hours too fill up the 1700l puffer for hot water. i think thats is quite long.
whats are yours settings of the boiler? should i go for lower lambda % ?
ps, sory to write in eng, cos i dont come from germany.