How hot do you consider hot ? - The phone will draw a lot of current through the charger, they will run hot.
If you have concerns then change the charger to another compatible one. I have only charged my phone a few times due to the large battery
Hot as ... starting to smell burned plastic, that hot.
Right now I'm using another charger from a different equipment with the same specs (Volts and Amps) and is a litle hot (that's normal), but not so hot as the charger from my umi
Hi
do not waste your time of warranty , buy another charger preferably 2A . I ordered two umi touch and both charger overheat and fail dice on the second day .