I have a hot springs spa with the iq 2000 controler and had the tri bend heating coil. It came with the house and worked fine for the first couple of months but then started popping the reset button on the coil all the time. Thought it was the coil so I bought what I thought was the new titanium watkins element off ebay although it actually appears to be a knock off. Anyways, it's still popping the reset button on the new element. The LM OK and HTR ON leds on the panel are illuminated. The display on the spa does not read the tubs temperature, just the temperature you adjust the tub to and then after a second it goes blank. Any ideas? Maybe the thermistors? Or does it sound like something else?

Also, the old element was a 6.0/1.5kw element and the new one is a 4.0/1.0kw element. Should that cause any issues, or just heat the water slower?

If the high limit keeps tripping it usually means that there is not enough flow.

The most common causes are dirty filters or a circulation pump problem (either clogged or dead).

The 4K heater will be fine.