I have a powermax 155 boiler which is not igniting. It has worked with no problems since I moved into my property which has been around 6 months. I noticed I had no hot water and saw that the boiler was locked out. I turned it off to reset. It atempts to ignite 3 times and then locks out. I have checked my gas valve which appears fine. My water pressure is just over 1bar. I have no wiring diagrams so I cant see what else would hold it off. What else can I check?