Hello epsiwebdev,

Thank you for posting in our community.

What I can suggest is using Sorting features columnSettings. This is a list with columsn settings that specify custom sorting settings for a specific column(whether sorting is enabled/disabled,default sort direction etc.). You could specify the column that you you would like to sort by its key and set it sorting direction. For example:

  $("#grid").igGrid({
                dataSource: data,
    features:[
     {
      name: "Sorting",
       columnSettings : [
                {
                     columnKey: "Age",
                     allowSorting: true, 
                     currentSortDirection: "descending"
                }
            ]
     }
     ]  

I created a small sample illustrating my suggestion and I am attaching it or your reference. In my sample Age columns is initially sorted in descending direction.

Please have a look at my sample and let me know whether it helps you achieve your requirement.

I hope you find my information helpful.

Pleas elet me know if you have any additional questions regarding this matter.

http://help.infragistics.com/jQuery/2015.1/ui.iggridsorting#options:columnSettings

When you define the column settings you can specify the 'firstSortDirection'.

See:

http://help.infragistics.com/jQuery/2015.1/ui.iggridsorting#options:columnSettings.firstSortDirection

Do note the differences in the CODE and the API for ASC and DESC.  Try both to see which one picks up.  More than likely a bug in the documentation.