Hi, thanks for replies.
When both CH and DHW are on and taps are open, boiler goes 1,2,4 and stays at 4 as long as the hot water is running. During this I get the following reading:
t1 - 50
t2 - between 42-45
t3 --
t4 --
FL - goes from 5.6 to 7.8 and stays at 7.7-7.8
nF - goes from 13 to 18 and...