IRS liens on Tax Sale, Montgomery Co. PA

[Karen Polis]

I'm looking at a property that's going up for tax sale and I see it has 2 open IRS liens on it. I know in other states, such as FL, the IRS has 120 days to redeem the property - they pay you back what you paid plus 6% interest. Not a bad deal. But I've heard that in PA there is no redemption period, though I'm not sure about that. 

Does anyone know the actual laws around IRS liens and Tax sales in PA? I'm not looking for the reactive "stay away from the IRS" kind of response, but actual legal knowledge in order to make a wise decision at the auction.

Thank you for your help.