You're right that that is a concern. I think I set mine for 190C? Don't remember. But as you infer, my goal is to get it slightly below melting temperature so the the other components' solder doesn't melt. (Disaster if they do, then the board gets jostled or you knock a component with tweezers). Then when you hit it with the air, just that component melts.

Also, it seems to not melt if you don't flux the pads prior. Not really sure why.