could be a problem with the level detection system - an air operated pressure switch located under the top cover. power off, remove cover and look for a round unit about 3 inches across. disconnect the black rubber pipe attached to it, blow down the pipe to clear any blockage and reattach. also try cleaning the filter unit. apart from that could also be a problem with the heater or thermal cutout? check out www.2ndwave.co.uk/manual.html
dan, January 2008