Please help! Our Potterton Puma 100e boiler locksout on the central heating system within a few moments of the boiler firing up - ie the green ignition light comes on but goes off very quickly. This only happens first thing in the morning after the boiler has been idle all night. It seems impossible that the boiler could have heated up much within those few moments. If I manage get up earlier than than the CH time switch is set to kick in and run the on-demand hot water then the CH will work without lockout. Similarly, later in the day CH starts up fine. In the morning it will eventually stay on after several pressings on the reset button (or after hot water has been run). The boiler is about 4 yrs old and we've had a pump replaced in that time. It seems to run fine (when it does) though it is a bit noisy - gurgles and bubbles. We do not have a BG maintenance contract and I'd like to be able point a CH plumber at the likely problem rather than have someone try this and that endlessly and expensively.
Thanks in advance.
Thanks in advance.