Hello all, this is my first post here. I have a Hot Springs Classic 120v that I just got used. When I picked it up, the guy said he had recently replaced the Main Pump and heater, but now the circ pump has givin out and he wants a new swim spa. I got it free, so I was willing to take on the project. I replaced the circ pump with the same one and had to replace a plactic elbow that was coming out of the heater tube then going to the circ pump. I filled it up and plugged it into a 20amp GFCI outlet. Now the main pump runs strong, but as soon I turn up the heater, pop goes the GFCI. I messed with it a few times and the same result. I then found I could turn the heater knob up just a little and could hear the circ pump run, but as soon as it gets to any numbers on the knob the GFCI is tripped. Is this a straight up heater element issue or should I look on further. I don't want to just replace stuff and it not be the prob. Thanks for any help.

Update, I unplugged the heater from the box, fired it up and turned up the heater knob all the way. I could hear a click (relay or something), but GFCI did not blow.

Your heater is indeed the culprit. You might want to take the old circ pump if you've still got it and plug it in to make sure the heater wasn't the problem the whole time.

This should be your heater element here, but I'd suggest emailing the guy your serial number or a pic just to be sure.

Thanks for your help, I have a new one on the way and you are right, the old circ pump was fine.

I could use your knowledge one more time to let me know if the circ pump looks like it is connected up the right way. I have seen some posts about the out let hose should go up and then down like a U. Also the pump was never bolted down, it is kind of held up by the hoses. Here is a pic.

You might be thinking of a blower or ozonator line, both of which are often installed with a hartford loop, which goes above the water line and back down again. The circ pump just needs to be hooked in going the right direction (pressure/suction lines attached on the corresponding barbs), which you've got covered. Screwing it down will cut down on any vibration noise and lessen the likelihood of that bit of plumbing leaking or coming completely undone in the future.