Ahhhh the wiring .......
There is ABSOLUTELY NOTHING wrong with larger aluminum wiring. The wiring that receptacles were on is smaller wiring and is now illegal and is/was very unsafe. There is a VAST difference.
One cannot accurately put out a blanket statement that all AL wiring is bad.
This is absolutely true, I have to say that mostly the lower amp wiring is the issue due to heat fluctuation with the outlets.
Changing out the larger wires to copper is a waste of time and money.
Petey could explain it better and in more detail I'm sure.
You need to find out the proper amperage to the unit to start, then look at the condition of the breaker itself.
If you have any branch circuit wiring which is AL you should have a licenced electrician evaluate it sooner than later.