I get woozy after it's been running a few minutes.
Barb shows no symptoms.
The carbon monoxide detecter shows nothing, but hell, it's 10 years old.
Not worth chancing it.
Turning off - wait for them to look at it tomorrow.
Let's review a few days ago.
EGC flushes something she should not have.
Toilet next to vent directly over furnace get a pretty big hit of water (and other things). Works that night. Stops working the next night.
Hmmmmm.
Heat exchange corrosion finally push over the edge?