I currently own a Sundance Optima hottub (probably 2005) and noticed a FLO error. I did replace the flow switch and replaced the filter to no avail. I also tried running it without the filter in it and left it powered down for 30 mins as well. All pumps seem to work when I push the buttons to turn them on. My father (who knows way more about electricity than I) ran a voltmeter on the heater and that appears to be okay, however, the tub is not producing heat. I am curious what the piece circled in red in my picture is. It connects from the fliter to the heater an I am thinking this may have went up. Any input is greatly appreciated.