Pckg,ISO Valve SD SVCE (BI-42SD,BI-48SD)
   NOTE:  Used to Add Isolation Valve to Units
          That Were Not Produced With One.
  BI-42SD Use Prior to Serial #4123992
          Starting With #4123992 See 7019463
  BI-48SD Use Prior to Serial #4123992
          Starting With #4123992 See 7019463