Performed diagnostic evaluation on 15-year-old Lennox furnace as a second opinion after another company tagged unit for compromised heat exchanger. Visual inspection revealed rust on primary heat exchanger eyelets suggesting exhaust leakage, and potential pinholes in secondary heat exchanger. Though unit remains operational, advised customer of risks associated with continued operation. Performed resistance testing and thorough component inspection with no additional issues found. Will follow up with heat exchanger replacement options and Lennox warranty verification.
