it sounds like your irn is pretty scared. parrots usually only bite as a last resort, after all other fear signals have been overlooked.
look at his body language. if his feathers are flat against his body, his eyes are pinning ( iris getting bigger and smaller rapidly ), he opens his beak, and is shaking slightly, those all can be signs of fear you may just not know to recognise.
try taking a few steps back. if he doesn't like stepping up, don't force him to. talking while near his cage and giving him treats are both great ways to earn his trust in you and show him you're nothing to be afraid of.
try and make every interaction with him positive. give him treats when you enter the room, and while you talk to him. so he associated your presence and voice with positive things. sunflower seeds or millet are very good treats.
what sort of things are you doing near his cage that scare him? are they very loud? are there any sudden movements involved? if you can, maybe change how you are doing those things so he's more comfortable with it. if it's something that has to be done ( refilling water and food dishes) maybe leave a treat in his cage so he knows that even though these things are scary he gets something nice from them too.
good luck with your new bird! please keep us updated