Please help! My tub is about 8 years old. It has always worked great until recently. No heat! Topside is calling for heat also flashing the dreaded 3 dots. I have 240v to board but nothing at heater. I changed pressure switch and cleaned filters but nothing! The service tech wants 900.00 for new pack so i sent board to one of these board repair guys who charged 100.00 and replaced heater relays and says that everything works fine in his shop. Now i'm lost! Any ideas??