You can download the Carrier Service Bulletin 09-0022 - Here
A flue gas analyzer is required.
I found a furnace today with over 9000 PPM CO in the flue! The supply air temp was low, 90F. The burner box and the top of the furnace were extremely hot. The roll out switch had tripped.
After showing the client the Carrier lawsuit documents they decided to buy a new furnace. I will tear it apart and see if the primary or secondary is cracked. My bet is on the primary.