Have a unit here that operates properly when on Inspection. ECD shows Code 90, operates fine. PLace on automatic, ECD shows a code 50 (no start signal) and a code 90 (power loss). I have all voltages, 24vac, +24vdc, +5vdc. I am suspect of a Main Board problem but am not a fan of replacing boards unles I am positive it is warranted. Anyone know what causes a Code 90? Feel relatively that the code 50 is a result of the code 90.
Thanks in advance for any assistance. Slider.