CliffT

That was the problem. I am positive that the old thermistor was not plugged in that slot before. Thanks for the help!

Did the screw driver test for three minutes. Heater did not turn on. Rather than strip the wire a taped the ends of the pressure switch harness together. See picture. I also added a video of the circ pump running. Still have the same problem. IMG_3701.MOV

Yes the circulation pump is running. One thing to note. When I installed the pressure switch it never got tight. Seemed like I could turn it forever. Is that a problem? Ill try the other steps although I’m not sure I’m following how to “Strip a small section on both pressure switch wires in thecable and twist them together to bypass the pressure switch.”

Okay I corrected that mistake. No change.

Do you mean the highlighted harness?

Sorry but I don’t understand what you mean.

Sorry about the upside down photos. I tried to get them in correctly but. No luck.

My HT has a flashing green light that I can’t seem to fix. The issue started with flashing red and green lights. Our hot tub dealer had us replace the pressure switch which led to a flashing red light. This time our HT dealer had us change the high limit and thermistor. Now we are at the flashing green light. What I’ve done so far. 1: Bled the circ pump line. 2: Tested ohms on new thermistor and high limit. Within 1 ohm of each other. 3: At this point dealer called Watkins tech support who said the control board is bad. Ordered board. 4: Installed board. No change. 5: Re-installed old board and old thermistor. No change. 6: Drained tub. Re-filled slowly through grey pipe. 7: Reset breakers several times during 1-5. 8: Have tried with and without filters. 9: Jet pump one and two working fine. 10: Cycled through the valves on each jet pump to be sure all lines were clear and all jets worked. After refilling the circ pump would not run. Cracked the wet side and got air and water and pump fired up. Green light still flashing. Opened up the waterfall valve and bubbles stop coming from bottom of tub. Close waterfall valve and bottom tub bubbles start again. I am here air crackling through circ pump. Bled pump again. No change. Removed 1/4 tube on back of heater to bleed air. No air escaped. No change. Any ideas?