If the receiver gets very hot to the touch that is a sign to be cautious. Or, if you crank things up and the receiver shuts down at louder levels, that is a sign it went into protection mode because it can't drive 4 ohm speakers at those levels without over heating.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85