Hi again. The heating engineer fitted a new control box (DKO 970) on Monday 19/Nov/12, as well as a new solenoid and a new photocell. This was following advice from Wallstar. I had previously passed on to him what you had said (not mentioning you by name!).
Since Monday the boiler start-ups have got considerably better, but not 100% yet. There have been SIX successful starts on the Danfoss programmer, but TWO failures to start.
However, the LED on the control box (DKO 970) no longer displays a flash code when the boiler has failed to start. Instead, when I take the cover off to access the control box's reset button, the LED is on constantly.
As ever, as soon as I press the Reset button, the boiler starts.
What, do you think, the LED is "saying" when it is on constantly?
Thanks!
PS: On Monday night we had several brief mains power failures in this part of South Lincs. Any significance?
MM