I have a 1998 cal spa. have to go below to adjust temp. the pump that runs when the heater runs , runs non stop. it is not heating but if i turn the heater dial down to below the current temp it shuts the "heater off" Everything else is great. Please help Thanks

You have a couple of possibilities.
1) You may have a bad heater, check the voltage going between the two leads of the element inside of the control box, if voltage is present between the two leads while it is "heating" then you have a bad heater, if no voltage exists then
2) check for continuity on the pressure switch while the circulating pump is running, if there is continuity (detach the wires first) then you problem is either a contactor or a circuit board (if you have one), if there is no continuity then your problem is the pressure switch.

We haven't had much time to test/use the spa. But the heater is still acting up. No matter what point it's set to on the heating dial, it still gets too hot. It's like the thermostat won't turn off the heater no matter what. If you still think I need to recalibrate the thermostat, can you help me determine, from the pictures, where it's located and what exactly I would need to do for correct calibration.

Thanks

Recalibrating the thermostat is an easy enough thing to do...but it is an absolute LAST resort, 9 times out of 10 the thermostat sensor "bulb" has slipped out of the drywell that is goes into and thus doesn't pick up any temperature at all. Therefore the heater remains on constantly, check the bulb and make sure it is in a drywell, if it is then follow the lead from the bulb and make sure it is not crimped or cut anywhere, if it is then you must get a new thermostat. Also check the contactor that controls to heater to see if it is gett voltage to the coil, if it is not then the contactor has been the cause of your problems by remaining on when told to turn off. Most people I reccomend a replacement to as opposed to trying to recalibrate it, if your not positive of what your doing when recalibrating you can potentially cause serious damage.