1998 carrier gas furnace. Combustion exhaust system is failed. Ignition system very worn with high resistance reading. Went over options on page hm9. Chose hm9b to complete both repairs. Assembled new exhaust system and replaced ignition. Cycled system and completed performance testing. Ran combustion analysis on furnace 25 ppm co/ 12% o2/ 360 degree stack temp. All okay at this time.
