Most Combi Boilers now have DHW temperature control with setpoint temperatures down to 35C.
A 35 or 40kw bolier may only have a minimum output of say 6kw and and minimm DHW flowrate (DHW flowswitch trip) of 2.0LPM.
If a SP of 35C is selected then a flowrate of 3.44LPM will maintain that temperature of 35C (from mains at 10C). However if the flowrate is reduced to 2.5LPM then the DHW temperature will rise to almost 45C (44.4C), will the burner then cut out as the dT is 9.4C?. The boiler flow temperature on CH is allowed up to 5C > than its setting before burner trip. Does the same apply when on DHW?, ie burner cut out at DHW SP+5C?.
A 35 or 40kw bolier may only have a minimum output of say 6kw and and minimm DHW flowrate (DHW flowswitch trip) of 2.0LPM.
If a SP of 35C is selected then a flowrate of 3.44LPM will maintain that temperature of 35C (from mains at 10C). However if the flowrate is reduced to 2.5LPM then the DHW temperature will rise to almost 45C (44.4C), will the burner then cut out as the dT is 9.4C?. The boiler flow temperature on CH is allowed up to 5C > than its setting before burner trip. Does the same apply when on DHW?, ie burner cut out at DHW SP+5C?.
