Hi all, we have a fairly old ideal classic FF260 , recently serviced. It fires up when Called to in the evening. However it won’t relight during the course of the evening when heating is called for. I fitted a new programmer but it didn’t cure the problem. The 3 way valve seems to work ok. What does work though is turning the system off at the mains and then turning it on again. The boiler then immediately lights. Would greatly appreciate any ideas, I’m wondering if it could be the pub in the boiler