Performed diagnostic on upstairs Lennox unit, upon arrival customer stated unit wasn’t working, checked tstst, no voltage, upon going in attic found light switch turned off, turned on power to get unit started up, upon sequence of operation unit started up, but upon blower wheel starting it would spark them trip main breaker, inspected furnace, noticed blower motor has been replaced at some point as well as control board, unit also has door switch disconnected which is a safety feature, upon looking at new board I can see burn marks in metal, probably came from previous control board, flu vent is not properly installed, goes from single wall to double wall, should be double wall out the way out roof, recommend repair flu vent, also noticed a lot of ducts are ripped, customer also complained that one of the bedrooms up stairs don’t have good airflow, system is short on airflow per the size of unit causing inadequate airflow, explained to customer we can make repairs and still find othe