Habitation Aircon

Hi just bought an Elddis Autostratus and it has a Dometic 1300 air con unit fitted, what i want to know is do i need to have it serviced, is it someting i can do myself and what should i look out for. also i am told that it is only for cold air as it does not have the heating part fitted (optional exta) can this still be fitted and again is it someting i can do myself
thanks