Hi, I have an Ideal ICOS HE24 condensing boiler (unvented system) and we have no hot water and no heat. The central heating programing unit is on and controls the automatic valves. What is not working is the boiler itself. It is completely off. Usually there is a green light on and you can hear the spark. Today it is dead. What should I do? Can I do something myself? Should I call someone? Who? Thanks for your help!