I have a Jacuzzi Platinum Series, Pinnacle Plus Spa. We got it used, had to replace the pump and it has been working flawlessly for over one year. One night we went to go in and the water temp down
and all of a sudden the breaker shut off. We checked the heater with a meter and found the element to be bad. I ordered a new element, was not as large as the one we took out, but was same 5.5. Replaced it, ran the tub, it heated to about 94 degrees and then same thing happened. Breaker blew, element was shot. Thinking perhaps we received a bad element, called the company and they sent a new one, same thing happened. We then did some reading and found we need a
"Low Flow heater" so we broke down and bought the complete unit from a Jacuzzi Parts company. Received it, installed it, ran the tub this time we got up to 100 degrees before the breaker blew and the heater was fried. We are at wits end, cannot figure out what could be causing the heaters to
be burning out. Any help or suggestions would be greatly appreciated.

Normally the only thing that will cause this is not enough water flow thru the element, or you've got air trapped in the heater.

It'll do it every time. Be sure you've got really good flow through the thing and it shouldn't happen.

I thought if there wasn't enough flow the heater/pump would automatically shut off to avoid the heater element burning out???

Well the way it works is - you can have enough water in the heater to keep the tube cool - but enough of the element can be exposed to air to cause it to overheat in a specific area.

Same thing can happen if debris builds up on the element - and it allows the element to get too hot in that location - but yet the heater itself isn't hot to the touch.

Where exactly on the elements are they burning up?