found Exhaust Fan left hood erring wash and check on the right side of the left hood. f found upper contact board has arc marks in it. I swapped boards but it still error-ed. I swapped boards and now both sides are working could not reach tech support. will try back Monday when they open. 12/3/19 Right side not working .Found unit error stays on the right side when I swapped wiring from boards manufacturer said that means the board is bad .Also contact board is in poor condition I will obtain parts and return. 12/13/19 arrived. customer took me to location. replaced right board in left hood. tested. unit is working OK at this time OK for use.