Gas company shut off furnace and hot water tank, they couldn’t tell what was putting off the high co levels. Old General Electric gas furnace (looks to be 1987)failed combustion analysis. Was reading 562 ppm of carbon monoxide in the flue vent before removing my combustion analysis tool. Left and center chamber are compromised giving off high levels. Furnace has been condemned and red tagged.Hot water tank was installed in 2018 and passed combustion analysis test. Customer is getting an estimate today for a new furnace from 3-5pm.