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Don't think you can do it. Back in the day you use to have to send the circuit board to Balboa and they would do the change on the board to alow it to go to a higher temp, took about a month+. You also had to sign a disclaimer that you would not hold them liable should someone die. Then they refused to do it all together because the health dept I believe deemed it unsafe for people. Same was true for major spa mnfg. I know on Jacuzzi's and Sundance you can make a change again to go as high as 106 not sure about H,Springs? You can probably call Balboa and ask them, would love to hear what you find out.. Maybe someone else here knows more??
The latest Marquis Coastal Reward spas use a Balboa M7 controller with2 thermistors near the heater. Balboa says the first (as water flows by)controls the water temp and the second is a 118 F safety limit. They mustagree within 2 F for the controller to work.If you wanted to make the controller think the water is 104 F when it'sreally 110, you might put a resistor in series with each thermistor nearthe control board. They have a negative tempco, with 22117 ohms at 90 F,17636 at 100, and 14158 at 110, so 104 F would make them about 16245 ohms,adding a 2.2K ohm resistor in series with each thermistor exposed to 110 Fwater will make the controller think the water temp is only 104 F.(Marcia got someone to do this, and it worked :-)Nick