Hello Simon, Often one of the problems encountered with a caravan is one of little usage, particularly of the gas appliances. All flame burning gas appliances have a tube between teh valve and the burner assembly, which is tapered. Its functionis to mix the injected with sufficient air to allow it to burn correctley. The size of the tube or venturi, is often very enticing to insects and they will often make thier homes in them. A spider web can be sufficient to prevent the gas mixing properly with the air usually resulting in a very yellow flame like a candle. This can reduce the effiecency of the flame. The other thing that comes to mind is the fact that even in british winters, the temperatures can fall low enough to cause butane gas to liquify in the pipework. When this happens you can cause it to drag with it soem of the oiley "heavey ends" of the gas which can block pipiework and valves. In view of the fact that thsi is a gas appliance, you should only uses suitably qualified people to service or repair it. Failure to do so could render your insuarance void, and may endange users of the van.