David Chapman wrote:

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


I posted this a while back. It refers to a 24i junior but maybe yours is
the same

"Just for the archives, the built in filling loop for this boiler
operates as follows:
Shove the plastic key up into the hole to the right of the white plastic
nut, turn clockwise (it locks at about half a turn). Then turn the white
plastic nut anti clockwise to fill the boiler"

IIRC it needs a bit of force to get the key all the way into the hole