If the pressure shown on the dial is low (outside the green zone) look under the boiler - there are several little taps in the maze of plumbing - turn the one at the front left as you face the boiler. You should hear a gushing sound as it lets more water into the boiler. Watch the pressure dial, it should go up very quickly, as soon as its in the middle of the green zone turn the tap off again. You boiler should restart itself if central heating is set on, otherwise run a hot tap and it should restart.
Lewis
February 2009
from
http://howtomendit.com/answers.php?id=184123
Steve, November 2013
