potterton combi 80 boiler lockout on?

I have mislaid service manual, aand my engineer can't find the answer to why the boiler continually goes to red lockout and won't fire up.I have to press reset button up to 14 times to get ignition and when it does ignite I fear one day it will blow the boiler off the wall. He has checked the pressure and topped water up with hose . Water runs scalding hot when alight and at poor rate. I'm fed up with running downstairs every morning to get ignition before my shower!! Any help gratefully received. Thank you