You should have a filling loop (braided silver pipe one end connected to mains water other to the boiler, if unconnected hand tighten the connection) located near or below the boiler. Opening this valve will cause any air to be expelled from the system aka bleeding the system. Using this valve maintain the pressure at about 1.0 bar whilst bleeding every radiator in turn. This usually is easier with 2 people. once complete increase pressure to 1.5 bar. Switch off the power to the boiler before attempting this.
skip, December 2009
