I have a Worcester Bosch 28i Junior combi boiler that I believe is about 5 years old (it came with the house we bought last year). It has always worked fine, but suddenly the central heating has stopped working. When there is a demand for central heating, the boiler fires up and the indicator light comes on to show that the burner is lit, but this only lasts a few seconds and the light goes off. The boiler continues to make a humming sound (the pump?) and no hot water is reaching the radiators. The system pressure is fine (just above 1 bar) and the hot water continues to work on demand - e.g. no problems taking a shower. I admit to knowing nothing about boilers, but I wondered if it might be something simple that I could do myself - especially as the hot water is working fine. Or should I just call someone out to take a look? I fear that may be quite expensive though. Any advice would be very gratefully received! Many thanks.