We recently had a new Worcester-Bosch Greenstar boiler installed and when it was commissioned the CH system was pressure-flushed and checked OK. I was told by the installer that the system normally runs at 1Bar pressure and was shown the white tap and square-headed screw underneath the boiler which are used to readjust the pressure if it drops. Unfortunately I didn't pay enough attention to this at the time and now I cannot remember the correct way to top-up the pressure.
I found that there was some air in one of the radiators a few days ago and when I 'bled' it out I noticed that the boiler pressure reading has dropped slightly so I would now like to correct things.
I'd be most grateful if one of this NG's experts could tell me the correct way to use the white tap and square-headed screw to re-pressurise the system. I'd also appreciate knowing how much the indicated pressure readings should vary between the boiler being idle and when it is supplying hot water drawing a bath,
Many TIA - Dave