Ring the manufacturers technical helpline
They will be able to talk you through simple tests to determine if
You can fix problem yourself
Or
You require a gas engineer
Asbestos
April 2017
C1 and F7 indicate a fault of some sort - that model is notorious for C1 and F issues.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.