private void Application_Error(object sender, EventArgs e)
{
 if (GlobalHelper.IsMaxRequestExceededEexception(this.Server.GetLastError()))
 {
  this.Server.ClearError();
  this.Server.Transfer("~/pageError.aspx");//redirect to pageError
 }
}

Public Class GlobalHelper
{
const int TimedOutExceptionCode = -2147467259;
public static bool IsMaxRequestExceededEexception(Exception e)
{
 
 Exception main;
 var unhandeled = e as HttpUnhandledException;

 if (unhandeled != null && unhandeled.ErrorCode == TimedOutExceptionCode)
 {
  main = unhandeled.InnerException;
 }
 else
 {
  main = e;
 }


 var http = main as HttpException;

 if (http != null && http.ErrorCode == TimedOutExceptionCode)
 {
  if (http.StackTrace.Contains("GetEntireRawContent"))
  {
   return true;
  }
 }


 return false;
}
}

If DirectCast(Me.Server.GetLastError(), System.Web.HttpUnhandledException).ErrorCode = -2147467259 Then
            Me.Server.ClearError()
            Me.Response.Redirect("adminError.aspx?id=maxRequestLength")
        End If