I have a 1900 sq ft home with a 5 ton 14 seer amana ac unit. Will I hurt the unit having my thermostat set at 69 or 70. is it set too low? We like it cool..

No. It will not "hurt" your a/c but it will hurt your wallet in that you will be using more electricity.

I wouldn't think that would be a problem as 70 is supposed to be the average setting for a home.