We have a Hotpoint WDD960 and after starting the drying cycle the machine stops with error F13. It will dry for a random amount of time before stopping so I am confused what the problem could be. Recently we had the main PCB replaced as the machine wouldn't respond at all so I am ruling this out as the problem. According to a google search, F13 refers to "Dryer fan or dryer thermisotor faulty" The odd thing is the machine isn't that old and the dryer has only been used a handful of times in it's whole life. We do have very high PH level in the water here meaning a lot of limescale build up so could this be the problem? Also the temp sensor would work for the washing cycle also would it not? The machine washes perfectly. Thanks!