I have an old Glowworm Fuel saver MKII (model 30) that was working fine, a few weeks ago I turned the heating off at the timer, then before we went on holiday I turned the hot water off at the timer to save gas. When we came back I turned the water back on but the main burner wont ignite, pump is spinning & water is moving, the solenoid valve on the boiler is getting 23/24V and clicking when the timer cuts in but still no gas flow through main burner. Pilot light is fine and always has been. Help!