I have been trying for months to figure this old thing out. I now have good power to the heater and only when called for. At the heater lugs I actually have 240v. But the thing won't heat up at all. After leaving it on for hours I still have nothing. But the voltage at the heater is still 240v. Does this mean the heater element is bad?

Have you ohmed out the heater?

Also, do you have a spa cover, and have you given it ample time to heat, and checked the temp. with a thermometer, not your hand?

If you're getting voltage, a bad element won't heat. Too check the element, simply check OHMS

I have a AMP-meter and a vohm to test it with. I have left it to heat for 24 hours straight and have no heat. Still reads 60 in the tub, and cold to the touch.

Not ohming out the heater element, I put a clamp on amp meter and set it to 20A, When I call for heat the meter changes from 0.00 to 0.65. This would indicate that the element is bad, correct? We are talking about a 20 year old plus tub, and that has never been replaced. I figured since I got the low amp reading that checking for resistance would probably be meaningless. Let me know what you think.

156 watts of usage huh... take forever and a day to heat up at that rate. You really should ohm out the element to be sure, but by the sound of it, you do have a bad element