Is it always tripping both the high limit and the GFI?

I just measured it again (the wires coming from the heater) and there's a resistance of around 11-12M from the hot to ground and the neutral to ground. I don't measure anything across the 110v legs from the plug when I take the wires from the heater loose from the control box. Maybe the insulation is breaking down. Just after it tripped the GFCI I tried reseting the limit sw and the GFCI and plugged it back in and it tripped the GFCI again.

Dan

We just posted at the same time - I'll hook it back up again and see.

Dan

based on the post you posted at the same time as my post, it does sound like it's leaning towards a bad element. The surefire way to tell is if the GFI holds when the element is completely disconnected. You should measure around 8-12 ohms between the hot and neutral of the element (not to ground). If you don't have any resistance (infinite) on these two test points then your element would be "open" and need to be replaced. While the element is disconnected, if you have resistance between the hot and ground or neutral to ground, it is likely to trip your GFI.

Hope this helps

I just hooked it back up and its running with the heater on. I didn't measure the ohms between the neutral and hot but its drawing the correct amps. The water temps still around 95 so I'll see what happens.

Dan

Now I'm confused. I started it up and let it run. I went to sleep for a couple hours, got up and it was off. The GFCI wasn't tripped and neither was the reset on the heater. I turned the breaker off and back on and it came back on.

Dan

It did it again. It's def. the reset sw. I can push the relay in with a screwdriver and it starts. The relay measures a voltage drop of 120v across it even though I try to reset it, so wouldn't that mean the reset sw is bad? What if I jumpered it out? I guess I could try that (with an 11' pole).

Dan

OK, I can jump out the reset sw and it comes on. What's the worst that could happen? As long as I'm not in it.

Dan

so it's not the GFI tripping... well the high limit reset will trip out if the reset switch is out of range, requiring replacement. If you leave it jumped out, your heater may run rampant and overheat, and could cause premature failure of the element, warping of the plumbing, buckling and cracking of the spa shell, the potential for a fire, and could also burst a pipe and cause a flood.

"your heater may run rampant and overheat"

but that's only if the thermostat doesn't shut it off, right?

Dan