I have a Purex Triton Minimax 350 NG heater. It has recently began to shut itself off before bringing the spa up to the proper temp. Regardless of control box temp setting the water in the spa tops out about 95 degrees. When the heater first fires up, all LEDs come on, the heater ignites and runs like a champ. It operates fine for awhile then shuts off. Once it shuts down only the LED for Power remains green. The service light has never come on. I have taken the top off and cleaned out the heat exchanger, taken the front of the unit off and cleaned it, and replaced the temperature sensor for the control panel - no luck. Any advice would be appreciated, thank you.