Hi , I have a 2004 Cal Spa Atlantic with a 5.5Kw 240V heat exchanger that just won't work.I filled it up to clean it after the winter, at that time it did heat. drained it , re-filled it and now it won't heat up. The heat led does not come on, no error message are being displayed. It is the 5000 Power unit. Any ideas would be greatly appreciated ? Pressure switch, fried heater or is it simply haunted ?

Thanks