I have a 1996 dimension one spa, circ pump worked 1st weekend, heated to 104, after if shut off, would not come back on, replaced pump, still wouldn't work, replaced pressure awitch, still didn't work, replaced pc board ( there was a line that seemed to not get power according to tech), still not working, have had 1 tech out 3 times, can't find problem. Heater shows it is working from amp reading. have tried to by-pass pressure switch, and have unplugged the 2 speed pump to see if it would work, nothing, have checked for air blockage. The 2 speed pump seems to come on twice a day like it is suppose to. heater light would flash 3 times before I replaced the circ pump, now light is solid when large pump runs. The new pump did work for 1 evening, then stopped. Any ideas would be great.

have you checked the high temperature cut-out switch? usually it's just a push button reset, if your spa model has one.

Also, when you say your heater is working, based on an Amp check, did you also check for voltage across the heater terminals? If you are for sure getting power to the element, and there is no heat, you would have a bad element.

Our tub doesn't have a reset, I wish it did. It is a 1996 Sierra model which we paid $1000 for, but have put $800 into since mid-May. As far as checking the voltage, I believe the tech did that, he checked it with 2 different meters. So if the element is bad, then the circ pump would not operate, but the heater would still show it is getting power? Can you easily explain how to check for voltage across the heater terminals? There is not much more that I can replace on this tub, and I guess the heater element would make sense, either that or the thermostat I was thinking. Thanks for helping me out.