Worcester greenstar utility 18/25 oil intermittent spark

[robbie77]

Hi,


The oil boiler - Worcester greenstar utility 18/25 is being temperamental when firing. I think I have narrowed it down to spark not always being present. When it fails to start often hitting the reset will get the boiler going but if not and I remove the photocell then I can't see a spark.
Giving the boiler a rest seems to fix this. Sometimes it behaves for a day but not normally longer than that. I recently had the tank filled with oil and the boiler was fine for a week but I think this is a red herring.
Couldn't see any lose wires

I thought maybe a control box issue (Bentone DK0 970) or maybe an ignition transformer (Danfoss EBI4 052F4030)
Visual inspection of both looks ok, no damage or swelling. Or maybe something else?

Any ideas welcome!

Thanks

 

[Terrywookfit]

solenoid coil.

 

[robbie77]

solenoid coil.

Yeah I swapped that recently. When I check for a spark by removing photocell and can't see one I can still hear the solenoid clicking?

 

[Terrywookfit]

are you keeping the cell in the dark,

 

[robbie77]

Yes. Covering the cell with my hand. Sometimes I will remove the cell, cover the end with my hand, see that the boiler is sparking then place the cell back in and it will fire. It's just intermittent.

 

[Terrywookfit]

The EBI can sometimes give intermittent spark.
I usually fit a new one from van stock and see if it cures the problem !

 

[robbie77]

Swapped the EB1 yesterday afternoon, so far so good......