Hi, I have a the above boiler which is approximately 5 years old. I switched off system to change gas cooker. House has been empty for 12 months due to renovation and thus I never turned boiler on. Now, when I have come to do it the boiler will not ignite and comes up with F.28 fault code. The manual tells me this could be a lack of pressure, iginition, no gas??? There is plenty of gas there as cooker and fire works fine. When boiler turned on it "clicks" 3 times and nothing happens. When reset button pressed nothing happens. Two Gas Engineers baffled. Can anyone help and shed any light please? Thanks