We recently had someone out to service our hot tub and replace a pump seal and open our tub for the season. Since we opened the tub it has overheated 3 times (We have an Aeware by Gecko Keypad K450 and it has displayed HL on the display). Each time it has done this we have opened the cover and shut the power off to the hot tub until the temperature comes back down. When we turn the power back on we set the temperature to about 90 degrees and after a couple of days we get the HL error again.
Is there anything we should be doing to stop the hot tub from overheating, or what could cause the HL error all the time?