Hi all! I have a 14 year old Jandy LT400 that we really only use to heat the spa. It worked fine the last time we used it, I guess it was a few months ago. Went to turn it on the other night and it started heating up as usual, but stopped around 87 degrees. I went out to the heater and found the Hi Limit and Service LEDs flashing. I found the Jandy troubleshooting flowchart online and went through that. I am getting appropriate voltage to and from the Hi Limit switches when the heater initially comes on (it runs for probably 15 minutes before tripping the light). When it trips, I'm not getting voltage out to the switches. According to the flowchart, this apparently means the GUI/control board is bad, but I'm not convinced. I'm concerned that it may be a flow issue and these components are doing exactly what they're supposed to do. Any heater experts out there that can help me out? TIA!