duke-one wrote:So a heating element that is leaking to ground is a grounded element, not a short.

Is that the grounded conductor, or the grounding conductor?
A short circuit is a colloquial term for one that takes a short-cut home. Whether it takes that shortcut through the grounded conductor (neutral/return) or the grounding conductor (ground/green wire) is fairly technical.
Where in the NEC does it differentiate?
My pet peeve is when an open circuit is referred to as a 'short'.

Well that was disappointing.....

I changed the cord thinking I had this all figured out but The GFI tripped again Again I didn't put together that the boiler is not isolated from the frame. As long as the frame is grounded by the ground wire the GFI will trip. (short from hot to ground.) As long as the the ground wire is removed either by using the adapter or by removing the ground wire from the grounding post on the frame the machine works fine.
This brings me back to where I started,only now I know the element works. My guess is that the element is shorting to the base even though it tests good. I think Doug from OE and Randy G are right

[quote="When I get the gfi throw I go ahead and plan to remove the element from the boiler and do all the tests with it on the bench to avoid any phantom conclusions and kiln the h.e. then retest and rebuild it as a matter of course.
This problem is actually pretty common.[/quote]

Randy G. wrote:So no GFCI trip with element unplugged and tripped GFCI when element is powered?
I would be two coffee beans (if you pay postage) that the element is the problem.

I think I'll give it a quick descale pull a few shots (making sure I'm not standing in puddle of water while licking the group head ) and starting thinking about pulling the element off the boiler for more testing.

This was a good way to reacquaint myself with the use of a multimeter and I learned that there is a big difference between Zero and infinite.

At least I still have LP & the TEA to play with.

I had a defective element on an HX that was doing the same thing. Found the true cause when I was shocked wiping up a spill and touched the frame while in contact with the water. In my case, the voltage was reading 110v from the frame to ground..OUCH! The element was still working and not blowing the breaker with the ground wire disconnected. On very close inspection a breach in the element was found allowing voltage to contact the water, thus the boiler, and then the frame until finally to an unsuspecting hand.

Carefully read with a vom from the ground of the outlet to the frame with the machine live and turned on. If you find ANY a/c voltage (and I'm betting you will else the GFI wouldn't trip) it will most likely point to a bad element