Any advice appreciated for this thread, Potterton suprima 80l started failing to light and got worse over time, insurance replaced gas valve, then wouldn’t run for more than 30-45 minutes then the same lighting issue. I can see the electrode sparking from the window and the boiler runs up to this point before locking out after 5 or so attempts. Insurance now saying it’s a circulation issue. However now the boiler is locking before it lights back to the same issue as before. Lights sometimes like 1 in 20 times.