I am thinking of purchising a used AQUAREST plug and play hot tub. The gentleman claims that there is a possible electrical problem. He states that you plug it in, and it shuts off after 1-2 hours. He states that there is a security plug on the unit, and he has no idea why it keeps stopping. You have to wait about 24 hours to plug it in again. He claims that the heater and the jets work. Do you have any idea what could be wrong with it, and, what would e the cost to fix it?