Boiler Flame To High?

[lordwoody]

I think my Potterton Suprima 60L Boiler flame is to high.

The boiler is noisier than usual, the flame is a bit yellow and the cabinet gets very hot to touch.
Its heating tha Rads and water fine though!

All the rads have been properly bled but it did not make any difference.

What could be causing this?

 

[Tibbot]

Incorrect or no servicing causing flame to vitiate because of dirty heat exchanger fins and or burner. Boiler is in a dangerous condition and requires the attention of a registered gas engineer before it's used again.