Brian, you were dead on with the relay support of the thermistor. After spending the past few days researching this, it turns out that the board's firmware had a major update. The only versions I've heard of are version r1.50, r1.55, r1.58, and r1.59. Apparently, the relay was added to the board in r1.59, allegedly because of the thermistor failure rate. My version is r1.58 - go figure, lol.
As I said, I researched this over the past few days and came across a very interesting thread on troublefreepool.com. The guy had my plan to create a solution to make the thermistor a quick-change deal, where he used screw terminals soldered into the board. After he got going on the project, he noticed two different boards - one with a K4 relay and one without. And then he gets very technical and I couldn't follow. He posted a number of schematics and says to disregard the K4 relay in the map if your board doesn't have it. Here's the link to the thread:
Trouble Free Pool - SWG PCB. I'll post the pics and the schematics below as well.
Now my question is, is there a way to add this relay..and if so, how would I go about doing that? Is that what this person did?
AQR Low Voltage Power Supply
AQR sub-sectional onboard Power Supply Schematic Diagram
Per the original poster from the board "Here is the missing section of the GLX-PCB-RITE Power Distribution Schematic Diagram to supplement the previous sub-sectional Schematic Diagram I posted above. This concludes the onboard Power Supply Distribution flow path on the board.
The primary function of the SPST K4 Relay is to bypass the Thermistor as described above. Pin# 15 of U5 (MIC5841YN) switches from Hi to Lo state within a few milliseconds after the AC power is turned on. Pin 15 remains Lo until the AC power is turned off. Disregard, the K4 from the drawing if your board does not have it!
OTOH, pin# 15 on the older AQR mainboard has no circuit trace and the output is not assigned. The Micro-Controller chip dictates the switching functions of U5. Presumably, a burned-in Flash and not sure if something my outdated programmer can read. For the skilled tech-savvy, a simple timer would do the trick when upgrading the board."