Jaguar Combi boiler

[rob jefkins]

Got a problem with a jaguar combi boiler. Burner fires up for a few seconds then cuts out. A few seconds later it fires up again and so on.
Boilers flagging up F2 on the diagnostics but the manual doesn't mention anything as regards to fault finding.
Tried ringing Vaillant (as this is ex protherm/glo-worm) but as usual no answer.
Can anyone shen any light on this??? I believe it to be a faulty FSD but will still need guidance for a parts number.
cheers

 

[LIFES A GAS]

Hi Rob, F2 is CH thermistor failure according to this manual, download it here: http://www.protherm.eu/upload/download/1117195074.pdf
Hope this helps, Martin.

 

[Billy Bob Bob]

similarities to a ariston,does sound like a ntc but strap out flow switch[if it has one] to prove that first,if its the diaprahm type it may have a small split