Try the following update. Note that I've retained the pressure conversions in the code, but they're commented-out so they won't do anything. That means you can reinstate them later on if need be.
Code:
Sub EQLConverter()
Application.ScreenUpdating = False
Dim lRow As Long, i As Long, j As Long, k As Long
Dim StrTmp As String, StrBit As String, StrConv As String, StrOut As String
With ActiveSheet.UsedRange
'Loop through each cell in column C
For i = 3 To .Cells.SpecialCells(xlCellTypeLastCell).Row
With .Cells(i, 3)
StrOut = ""
'Split the cell results by spaces for parsing
k = UBound(Split(.Text, " "))
'Process each 'word'
For j = 0 To k
StrTmp = Split(.Text, " ")(j)
If Len(StrTmp) > 0 Then
'See what the 'word' ends with
Select Case UCase(Right(StrTmp, 1))
'If it ends with ', try a ft:m conversion
Case "'"
StrConv = Replace(Split(StrTmp, "'")(0), "(", "")
If IsNumeric(StrConv) Then
StrOut = StrOut & " " & Format(StrConv * 0.3048, "0.0") & "m" & " (" & StrTmp & ")"
Else
StrOut = StrOut & " " & StrTmp
End If
'If it ends with ", try an in:mm conversion
Case """"
StrConv = Replace(Split(StrTmp, """")(0), "(", "")
StrConv = Evaluate(Replace(Replace(StrConv, "-", "+"), "'", "*12+0"))
If IsNumeric(StrConv) Then
StrOut = StrOut & " " & GetDiameter(CSng(StrConv)) & "mm" & " (" & StrTmp & ")"
Else
StrOut = StrOut & " " & StrTmp
End If
Case Else
Select Case Right(StrTmp, 2)
'If it ends with FT, try an ft:m conversion
Case "FT"
StrConv = Replace(Split(StrTmp, "FT")(0), "(", "")
If IsNumeric(StrConv) Then
StrOut = StrOut & " " & Format(StrConv * 0.3048, "0.0") & "m" & " (" & StrConv & "')"
Else
StrOut = StrOut & " " & StrTmp
End If
'If it ends with IN, try an in:mm conversion
Case "IN"
StrConv = Replace(Split(StrTmp, "IN")(0), "(", "")
If IsNumeric(Left(StrConv, 1)) Then
StrConv = Evaluate(Replace(Replace(StrConv, "-", "+"), "'", "*12+0"))
End If
If IsNumeric(StrConv) Then
StrOut = StrOut & " " & GetDiameter(CSng(StrConv)) & "mm" & " (" & StrConv & """)"
Else
StrOut = StrOut & " " & StrTmp
End If
Case Else
'If it's not ft/in and we haven't reached the end, look for other possibilities
If j < k Then
StrConv = Replace(Split(StrTmp, """")(0), "(", "")
If IsNumeric(StrConv) Then
'If the next 'word' is IN/INCH, do an in:mm conversion
If UCase(Left(Split(.Text, " ")(j + 1), 2)) = "IN" Then
StrConv = Evaluate(Replace(Replace(StrConv, "-", "+"), "'", "*12+0"))
StrOut = StrOut & " " & GetDiameter(CSng(StrConv)) & " mm" & " (" & StrConv & """)"
j = j + 1
'If the next 'word' is GPM, do a GPM:CMH conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 3)) = "GPM" Then
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0.0") & " L/Min" & " (" & StrConv & " GPM)"
j = j + 1
'If the next 'word' is GAL, do a Gal:Ltr conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 3)) = "GAL" Then
Select Case StrConv * 3.785412
Case Is >= 100
StrOut = StrOut & " " & Format(StrConv * 0.3785412, "0") * 10 & " Ltr" & " (" & StrConv & " GAL)"
Case Is >= 10, Is < 100
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0") & " Ltr" & " (" & StrConv & " GAL)"
Case Else
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0.0") & " Ltr" & " (" & StrConv & " GAL)"
End Select
j = j + 1
'If the next 'word' is GPD, do a GPD:LPD conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 3)) = "GPD" Then
Select Case StrConv * 3.785412
Case Is >= 100
StrOut = StrOut & " " & Format(StrConv * 0.3785412, "0") * 10 & " LPD" & " (" & StrConv & " GPD)"
Case Is >= 10, Is < 100
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0") & " LPD" & " (" & StrConv & " GPD)"
Case Else
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0.0") & " LPD" & " (" & StrConv & " GPD)"
End Select
j = j + 1
'If the next 'word' is G/HR, do a G/HR:L/HR conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 4)) = "G/HR" Then
Select Case StrConv * 3.785412
Case Is >= 100
StrOut = StrOut & " " & Format(StrConv * 0.3785412, "0") * 10 & " LPH" & " (" & StrConv & " GPH)"
Case Is >= 10, Is < 100
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0") & " LPH" & " (" & StrConv & " GPH)"
Case Else
StrOut = StrOut & " " & Format(StrConv * 3.785412, "0.0") & " LPH" & " (" & StrConv & " GPH)"
End Select
j = j + 1
'If the next 'word' is LB, do a LB:KG conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 2)) = "LB" Then
Select Case StrConv / 2.20462
Case Is >= 100
StrOut = StrOut & " " & Format(StrConv / 2.20462, "0") * 10 & " KG" & " (" & StrConv & " LB)"
Case Is >= 10, Is < 100
StrOut = StrOut & " " & Format(StrConv / 2.20462, "0") & " KG" & " (" & StrConv & " LB)"
Case Else
StrOut = StrOut & " " & Format(StrConv / 2.20462, "0.0") & " KG" & " (" & StrConv & " LB)"
End Select
j = j + 1
'If the next 'word' is FT^2, do a FT^2:M^2 conversion
ElseIf UCase(Replace(Split(.Text, " ")(j + 1), ")", "")) = "FT^2" Then
StrOut = StrOut & " " & Format(StrConv / 10.76391, "0.00") & " M^2" & " (" & StrConv & " FT^2)"
j = j + 1
'If the next two 'words' are SQ. FT., do a FT^2:M^2 conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 2)) = "SQ" And UCase(Left(Split(.Text, " ")(j + 2), 2)) = "FT" Then
StrOut = StrOut & " " & Format(StrConv / 10.76391, "0.00") & " M^2" & " (" & StrConv & " FT^2)"
j = j + 2
'If the next 'word' is PSI, do a PSI:KPA conversion
ElseIf UCase(Left(Split(.Text, " ")(j + 1), 3)) = "PSI" Then
StrOut = StrOut & " " & Round(StrConv * 6.894757, 0) & " KPA" & " (" & StrConv & " PSI)"
Else
StrOut = StrOut & " " & StrTmp
End If
' Test for a cell containing a numeric range
'ElseIf InStr(StrConv, "-") > 0 Then
'If IsNumeric(Split(StrConv, "-")(0)) And IsNumeric(Split(StrConv, "-")(1)) Then
'If the next 'word' is PSI, do a PSI:KPA conversion
'If Left(Split(.Text, " ")(j + 1), 3) = "PSI" Then
'StrOut = StrOut & " " & Round(Split(StrConv, "-")(0) * 6.894757, 0) & "-" & Round(Split(StrConv, "-")(1) * 6.894757) & " KPA" & " (" & StrConv & " PSI)"
'j = j + 1
'End If
'If the next 'word' begins with IN or Hg, do an in:mm conversion
'If UCase(Left(Split(.Text, " ")(j + 1), 2)) = "HG" Then
'StrOut = StrOut & " " & Round(Split(StrConv, "-")(0) * 25.4, 0) & "-" & Round(Split(StrConv, "-")(1) * 25.4, 0) & "mm" & " (" & StrConv & """) Hg"
'j = j + 2
'End If
'If UCase(Left(Split(.Text, " ")(j + 1), 2)) = "IN" Then
'StrOut = StrOut & " " & Round(Split(StrConv, "-")(0) * 25.4, 0) & "-" & Round(Split(StrConv, "-")(1) * 25.4, 0) & "mm" & " (" & StrConv & """)"
'j = j + 2
'End If
'End If
Else
StrOut = StrOut & " " & StrTmp
End If
Else
StrOut = StrOut & " " & StrTmp
End If
End Select
End Select
Else
StrOut = StrOut & " "
End If
Next
StrOut = Trim(StrOut)
If InStr(StrOut, " X ") > 0 Then
StrConv = ""
For j = 0 To UBound(Split(StrOut, " X ")) Step 2
StrTmp = Split(StrOut, " X ")(j)
For k = 0 To UBound(Split(StrTmp, " ")) - 1
StrConv = StrConv & " " & Split(StrTmp, " ")(k)
Next
StrConv = StrConv & " * " & Split(Split(StrOut, " X ")(j + 1), " ")(0)
StrConv = StrConv & " " & Replace(Split(StrTmp, " ")(k), ")", " x ")
StrConv = StrConv & Replace(Split(Split(StrOut, " X ")(j + 1), " ")(1), "(", "")
Next
For j = 1 To UBound(Split(StrOut, " X ")) Step 2
StrTmp = Split(StrOut, " X ")(j)
For k = 2 To UBound(Split(StrTmp, " "))
StrConv = StrConv & " " & Split(StrTmp, " ")(k)
Next
Next
StrOut = StrConv
End If
.Value = Trim(StrOut)
End With
Next
End With
Application.ScreenUpdating = True
End Sub