Getting a formula to calcualte only of the lenth of the string in a cell is more than 3

Hi all, I'm looking at improving this formula

=IF(NOT(ISBLANK($A28)),IFERROR(VLOOKUP($A28,InstallTemp!$C:$J,2,FALSE),0),"")

Where in A28 is a number or text string. But sometimes in this cell is "0" so I want to ignore that

I origianlly had

=IF(ISTEXT($A28),IFERROR(VLOOKUP($A28,InstallTemp!$C:$J,2,FALSE),0),"")

but when A28 is a 4 digit number it displays blank.

So i was thinking of something along the lines of =IF(LEN($A28)<3,IFERROR(VLOOKUP($A28,InstallTemp!$C:$J,6,FALSE),0),"") but i cant get that to work.

Any Ideas,
Thanks in advance.

John