The boilers water pump does not have enough pressure to top up pressure through filling loop have to do it by manual water hand pump
The two matters to which you refer are totally unconnected. The pump in the boiler is to circulate heating water around the heating system. If you cannot pressurise the system with the filling loop properly then the boiler should not have been installed in the first place. A combi boiler needs a minimum working pressure and flow rate to work properly. I would suggest firstly you get the installer back if its just been fitted or contact the water board to see why you pressure is so poor.
