How can I get water runing in mySwift Sundance 590rl?

Hi,I have a Swift Sundance 590RL motorhome and recently went a way in it for the weekend unfortunatly I could not get the water to run in neither hot or cold.
I had the heating on for about three days before I went away and when I came back I put the heating on again plus my halogen heater in case the pipes may have been frozen but it still will not work.When you turn the tap on you can hear a gurgling noise and can feel some air I just wondered could there be an air lock and if so how would I go about clearing it are if not any other advice would be very gratefully appreciated,
many thanks Kenny.