Thread: VLOOKUP range too large?

I have been trying to get VLOOKUP to scan for data on another worksheet. The data sheet is fairly large and most columns are formulae, dependent upon manual data input from a few other columns. The fifth row has been drag-copied down to row 3000, so that when new data is entered, the formula are ready and waiting.

It works well (as it is described to), yet it seems that when the table range exceeds a certain value I get DIV/0 error. For instance: =VLOOKUP(B7,MFCS!$U$5:$AN$1822,20) works fine for this sheet, yet VLOOKUP(B7,MFCS!$U$5:$AN$1823,20) does not! Keep in mind that each row is EXACTLY the same as its' neighbors above and below, as I used a simple corner-drag-down to create them. Manually inputed data (and their correspdonding formula responses) are entered over time (48 points per day), and row 1822 is well past the row it needs to look to find the right value at this moment. However this will change over time. I expect to need it to scan to row 3000 by the time the sheet is finished. Another note, on other sheets, this working range (row 5 to row 1822) changes drastically. Help!

Column U is in ascending order (0, 0.5, 1.0, 1.5, 2.0 ...), and it is not looking for exact values. However, after the last inputted data, each subsequent line displays a "0". I manually erased the remaining zeros, and the problem seems to have resolved itself, though this leaves two issues: Why it caps out at 1822 (versus any other row that has a zero in the U column), and how can i get the value in column U to stay blank if it is receives no input?

thanks