Validity of a hindu marriage without any pheras.

In my opinion, satapadi is absolutely essential for a valid Hindu Marriage. 

if zero-pheras is what the other side is insisting upon, i would suggest you to go for a Court marriage under the provisions of a Special Marriage Act.   

Hi! As rightly suggested above, section 7 of the Hindu Marriage Act lays down that the sacred act of Satapadi would be essential to solemnize a marriage between two Hindus. (Refer to section 7A of the act, as well as S Nagaraj case, as there also exists an amendment which does away with the necessity of Satapadi. It may or may not apply to this case depending upon the case's circumstances.)

However, of course, the parties can also choose to marry under the Special Marriage Act. For that, no ceremonies would be necessary for the solemnization of marriage, just a few steps to be taken like sending of notice to the Special Marriage officer of the parties' district, and so on as per the act provisions.