How can I fix my heating, caravan, Eldiss Nobility?

the heating and hot water system has packed up it is Primus and have no idea what the problem is. Should work on Gas /Electric but only did work on gas. Have had caravan 7 months but is about 15 years old, would be grateful for any info or anyone that can look at it or knows a man who can. It is stored near Romsey Hampshire

Barb
May 2011