Thanks in advance for the help. I haven't seen another question and answer matching my issue.
I have an old Goldline Auqa Rite controller, firmware 1.33, that's 10-15 years old. We bought the house this summer and diagnosed a bad T-CELL-15 salt cell soon thereafter, replacing it with a new TCELL940. It worked fine until recently, when I noticed the current goes to 0 after about 15 minutes. This is with the controller in super chlorinate or 100% auto. It continues showing the POWER and GENERATING lights but no others. The displayed voltage is 30.6V when the current is 0.
Water temperature is 55-60F.
The flow sensor went bad soon after replacing the salt cells; I replaced it and there have been no error lights since. I've tried various speeds on the pump to no avail.
I inspected the salt cell, and it looks fine inside with no calcium build-up.
When running, the controller displays the salt level is in the 3600-3900 ppm range. However, two salt test strips from different brands measure 2600-3000 ppm.
Chlorine is around 3 ppm with a couple days of manually reseting the controller to get it to run longer.
pH is about 7.4.
Hardness, alkalinity, stabilizer are high after the previous owner didn't change water; I'm waiting to change until I get the chlorinator and heater fixed.
I opened the panel and don't see any immediate signs of damage. I'm an electrical engineer and have read about replacement thermistors, rectifiers, relays, etc. I verified that all the LED's still illuminate, at least when checked with a multimeter's diode check mode. The thermistor gets hot to the touch, and my problem doesn't match what I've read about a failed thermistor. It seems like the relays are working.
I stayed around the controller for long enough this morning to think I heard a click when it went to zero current, but I'm not 100% sure. I was thinking to further troubleshoot the board next, e.g. probing for output voltage, but I'm also wondeirng if I should just update to a newer board. Is there protection circuitry inside the controller which would cause it to open the output circuit?
The TCELL940's label says 24V and 5A max. The controller starts up fine and settles to about 25V / 5A, but then goes to 0 current after a while. It does go a bit above 5A, perhaps 5.21A, and also gets into the 25.1V range. I'm wondering if there's an overcurrent or overvoltage protection in the TCELL940 that's opening? I've also seen mention that the 40,000 gallon salt cells go up to ~8 amps. I asked when replacing the salt cell and was told the 940 would be fine with my old controller.