I have an OLD hot tub (pre circuit board models) ... I've been able to maintain it for years.
However, I'm stumped. The house breaker (not the tub GFI) trips when the heater thermostat is turned up and turns on (while the pump is running).
I've disconnected all .. even the pump. When I manually depress the pump contactor/relay with the thermostat up ... "trip".
I've looked over all the wires and connections and I don't see corrosion or strange stuff. Just not sure what component could cause this.
Flow sensor is new and adjusted (seems to work fine) ... internal fuses are good.
I even turned the thermostat up, engaged the flow sensor (without the pump running) .. it DIDN'T trip the breaker.
I still need to check the heating element .. but, I'm doubting that's the issue.
Just looking for some thoughts ......