You could try something like the following:

Public Sub ConditionalFill()

Dim val As Long
Dim nr1 As Long
Dim nr2 As Long
Dim nr3 As Long

val = ActiveCell.Value
nr1 = Range(ActiveWorkbook.Names("namedrange1")).Value
nr2 = Range(ActiveWorkbook.Names("namedrange2")).Value
nr3 = Range(ActiveWorkbook.Names("namedrange3")).Value

Select Case True
Case val nr1 And val < nr2
ActiveCell.Interior.ColorIndex = 6
Case val nr2 And val < nr3
ActiveCell.Interior.ColorIndex = 5
Case Else
ActiveCell.Interior.ColorIndex = xlColorIndexNone
End Select

'If val nr1 And val < nr2 Then
' ActiveCell.Interior.ColorIndex = 6
'ElseIf val nr2 And val < nr3 Then
' ActiveCell.Interior.ColorIndex = 5
'Else
' ActiveCell.Interior.ColorIndex = xlColorIndexNone
'End If

End Sub


Personally, I would use the If..ElseIf structure (commented out)
instead of the Select Case. First, it's more intuitive to code, and
second it's reportly faster.

Also, the above code assumes Long for the cell value type - change that
as need be.