After a lightening strike next to my house, my Fujitsu ARU12RLF system stopped working. I have a Google Next thermostat, and a UTY-TTRXZ1 converter board. Tested the 24V AC power supply, seemed fine. I swapped back in the original Fujitsu thermostat, and the system worked again. So I ordered a replacement UTY-TTRXZ1, reconnected it, and the system still doesn't work. I checked the LEDs on the board. Blue LED is off, Green LED flashes once, second (Red) LED flashes twice, and third (Red) LED flashes continuously.

The manual indicates this is a controller error. The frustrating thing is that it's clear the board is trying to communicate the error, by the number of flashes of the first (green) and second (red) LEDs. The manual even has "(n)" for the number of flashes, to show that it will vary. But it provides no details as to what the flash counts mean, and I've found no information online about it as well.

So...any ideas here? Is it possible there's a problem with the actual system, and the original Fujitsu thermostat is just more forgiving (or ignoring the error codes coming back???)