Hi we have recently purchased a secondhand caravan a Adria Optima 400 main uses will be for weekends away at the track as my son does motorcycle racing, just a few questions in the toilet/shower the shower head has red banding on it does this mean it is suppose to have hot water to it, as reading on the net i can not find out wether it should have hot water or not.Any any advice on such caravan would be much appreciated.