Three lights are on the panel green red and amber
Green on only unit ok (water hot)
Green and Red unit failed to light (water cold)
Amber low current in the leisure battery.
go to www.arcsystems.biz if you want a manual to download.
Green on its own shows unit working
Green and red shows it failed to light as you haven't seen red with the green you should get it checked out at your service centre. At a guess you MIGHT have a gas module fault. Look up ones that come to you save dragging it to a service centre and may be cheaper. Ensure they are covered to work on LPG appliances (Low pressure gas) (U.K gas rules apply)
www.ukcampsite.co.uk type in search carver cascade for forum feed back there is a good article from the above arcsystems.biz website. can't copy it due to copyright on the page.
Bob UK
February 2014