Potterton kingfisher II Boiler?

Boiler pilot light is just on a small flame setting (pilot light). Have tried several times to fire it up to full flame on the black knob setting, but to no avail.

I left the control unit (programme timer unit) to the 'once' setting on the timer, and have noticed after 3hrs the radiators upstairs are warm but the downstairs rads are very cold?

I'm confused if whether the boiler is working or not, and can not understand why the rads upstairs work, and the downstairs does not? The hotwater 'white dial' located inside the boiler unit, is set to position 3 (5 is maximum). The water seems normal and hot enough, eventhou, its weird that the rads downstairs are so cold?.


HELP!!!