I suspect the OP's boiler is over powered and is short cycling.
Reduce d0 to say 14 kW and see what difference that makes!
Also need to see the setting of the auto bypass valve and the flow and return temps ( d40 and d41 )
Tony
Reduce d0 to say 14 kW and see what difference that makes!
Also need to see the setting of the auto bypass valve and the flow and return temps ( d40 and d41 )
Tony