Advice on pump settings

Hi All,

Fitted a willow Yonos Pico pump 25-1-6-130 after the advice on here. What I'm confused about is the pump needs to be set for head at either. 1-4 mtrs or 1-6 mtrs (see below attachment) my system has 8 radiator's and is a closed pressurised system.
I worried if I pick wrong setting I'll over pressure system or cause some other issue. Tried to Google but really can't understand this head thing.
Old pump only had a three speed settings.
Thanks so much for any support around this.

You can set it to C2 which is a constant curve setting of ~ 3.8M like the old 3 speed only pumps which should be quite sufficient for your 8 rad sysem, it will propobably show a power output of ~ 23W (watts) or like mine, keep turning the setting knob anti clockwise past C1 until it reads a proportional pressure (PP) setting of 4.6M (flashing for a few seconds) this will then give a effective head of ~ 3.6M and ~ 23W falling to ~ 16W if thermostatic rad valves (TRVs) are installed and throttling as the room temperature increases. You can also turn the setting knob clockwise past C3 until it shows a flashing constant pressure (CP) setting of say 3.6M which again willl/should do the job for you, you can't overpressure the system.

You pump might be more modern than mine it that it might show the flow rate in m3/hr as well as the power output, (something perhaps like 0.6 to 0.7 m3/hr), you might post your final settings.

Easiest way start on the lowest and run the rads if all heat up and are happy eg even heat from top to bottom leave it or if some don’t heat up upp it a bit eg next notch