Mikepier wrote:

Sorry for posting late, but for some reason, I saw no new posts for
about a week on this group.

Google sucks for Usenet access. Get yourself an offline reader and a
free server- You'll thank yourself.

Anyway,I found my problem. It was my attic fan. Hard to believe since
I live in a split and the attic fan is 2 stroies upon the other side
of the house with adequate ventilation from the roof vents. I don't
know if getting a slower motor would help, but the motor I have on
there now is 4 amps.


That's step one-- you've located the culprit and it is negative
pressure. For the summer, a cracked window in the basement should
cure it. I might consider a backwards dryer vent [something a
little more elegant is likely out there] to keep that pressure from
going negative.

I do have central air, but when I shut it off, the draft on the water
heater was still no good. Thats what made me think about the attic
fan.
I have a CO detector in the furnace room just in case.

If you have a good digital one it will tell you what the highest level
of CO has been. I'd check it weekly for a while to see if it has
been spiking just under the set-off level. Because CO is a
cumulative poison, you want to keep close track of it over the long
haul.

Jim