Ignition Problem with Halstead Quattro Boiler ?

I have a problem with a Halstead Quattro Boiler, When switching on the hot water and/or the heating, the ignition light comes on however the boiler does not fire up.
I have to press the ignition lockout button a number of times before it fires up and it could last only five mins before it cuts out and again i have to restart by pressing the ignition button.
Appreciate any advice. Thanks