Upon arrival inspected system and found unit in ignition failure code 4. Flame sensor was filthy igniter tested at 120ohms standard M style igniter. Test run unit with clean flame sensor and had no issues. Found vent pipe had multiple splits in pipe allowing exhaust gases to leak. Repaired with tape to keep system safe while temporarily operating and quote repair to vent pipe three 5 foot sections of 4” pipe and 3 90° 4” standard 1 90° 4” double
