Blue Ridge Spa (240V), existing installation.
I have a GFCI tripping problem that initially occurred intermittently but quickly progressed to the point that the breaker would not reset. Through researching the forum, I pretty quickly narrowed it down to the heater. When the heater is unplugged from the controller, the spa will remain powered and the circ pump will run. I bought a new heater and installed it and the spa powered up and ran for a few minutes then the GFCI tripped again. Now, same as before, the GFCI trips immediately anytime the heater is plugged in. It doesn't matter if the controller has the heater on or off, the breaker will trip as soon as the heater is plugged in. I don't see any visual problems on the controller board or with any of the connections and I have proper voltage readings between the terminals and with neutral at the receptacle. When testing the heater, I get 11 Ohms between the terminals and around 5 MOhms between the terminals and ground. 5 MOhms seems like a pretty "open" circuit, but I'm not sure how sensitive the GFCI is. Does this measurable resistance between the element and housing indicate that this new heater is bad? Thanks for any advice.