I am helping a friend get their spa up and running. When we turn it on it runs for 20 mins then shuts down;the 70amp breaker trips. Narrowed it down to when the heat is on but checked heaters and both look almost new. Has a (fls) or switch on one of the heaters that has adjustments but not sure how to adjust the wheel (up or down or if it matters). Also it has some overload switches for the aerator, pump and heater but none of them ever trip. One of the relays (2) is moderately rusty I havent checked them yet but think one runs pump high and low and the other is the heater or aerator not sure what tocheck at this point. I can send pics if it would help.